Chapter II

2.2    Population and Land Use

    2.2.1   Population: Levels, Growth, Distribution and Movements

2.2.1.1   Levels and Growth Pattern

In 1995, Zamboanga City had a total population of 511,139. It had increased two and half times over a 25-year period. This enormous growth may be traced to the rapid growth experienced between 1970 and 1980, when the City’s population was increasing at a rate not lower than 5% per annum. The growth lost its momentum in the early 80s and plummeted to a rate of 2.55 percent per annum. However, the rate started to pick up again during the first half of the decade (1990-1995), registering an average of 2.74 percent annual growth. Assuming the persistence of the current rate of growth, the 1997 mid-year population of the city is projected at 536, 906.

To trace the source of growth of the City, the increase in population was broken into two components: natural increase and net migration. Natural increase is the difference between the number of births and the number of deaths during a specified period. Net migration, on the other hand, is the difference in-migrants of the city during the same period. Given the population levels and the natural increase between periods, the increase or decrease in population due to net migration can be calculated. The following table illustrates the decomposition of population growth of Zamboanga City in terms of absolute figures for the periods 1980-1990 and 1990-1995.

To summarize, between 1980 and 1990, 75 percent of the increase in population was accounted for by natural increase, and 25 percent by net migration. However between 1990 and 1995 the contribution of natural revenue to the population growth dropped to 70% while growth due to net migration went up to 30%.

To interpret the population growth decomposition in terms of growth rates, the rates of natural increase (RNI) and the net migration rate (NMR) were calculated. The results were as follows:

The above table indicates that the rate of growth of the city due to natural increase remained constant from 1980 to 1995. Net migration rate, on the other hand, increased by 0.2 percentage points. Clearly, the increase in the growth rate from 2.55 percent between 1980 and 1990 to 2.74 percent in 1990-1995 can be attributed to the increase in the net migration rate. 

While the country experienced a steady and consistent decline in the population growth rate, both Region IX as a whole and Zamboanga City posted an undulating and abrupt pattern of change in their growth rates. (See table II-4).

Note: Region IX’s estimates of growth from 1970 to 1990 included Sulu and Tawi-tawi.

However, it is important to note that as the country experienced a significant decline in the population growth during the period 1980-1990, the respective growths of the whole region and the city decelerated at a much faster rate. This significantly sharp descent coincided with the intensified population and family planning campaign program during the 80’s. Apparently, the program had created a significant impact on the natural increase of population in Zamboanga City and the entire region.

The City’s population as a percentage of the region’s population for various periods is presented in the table below.

  Note: Region IX’s population from 1970 to 1990 included Sulu and Tawi-tawi

The proportion of the population of Region IX residing in Zamboanga City rise steadily, consistently. However, while the population of the region decreased considerably during the 1990-1995 period the proportion of the region’s population accounted for by Zamboanga City, increased abruptly. Apparently, this was due to the region to form the ARMM with other Muslim provinces.

The growth pattern of Zamboanga City is compared to other cities of Mindanao in Table II-6. It is significant to note that while Zamboanga City had the fastest growing population between 1970 and 1975 among the four cities, it lagged behind in the recent years. While the other three cities were at their peaks of growth between 1975 and 1980. The peak growth of Zamboanga City slowed down slightly

Table II-6.   Population Growth Rates of Selected Cities: 1970-1995

The abrupt changes in the population growth patterns of the four cities could be responses to their rapidly changing economic and social structures. For instance, after suffering a very abrupt declivity in growth during the 1980-1990 period. General Santos City posted a high 5.14 percent annual growth in the next 5- year period. Apparently, the main reason for this was the increased volume of in-migration to the City, which in turn was influenced by the influx of investors attracted by the existence development inputs in the form of major infrastructure facilities (e.g., fishing port and wharf, airport facilities, roads, etc.)

2.2.1.2   Population Age-Sex Structure

The age and sex composition of Zamboanga City’s population in 1995 is shown in Table II-7 and graphically illustrated in Figure II-1. The over-all sex ratio approaches 100, meaning, there is one male for every female in the city. In terms, of absolute number, the males slightly exceeded the females by 148. The sex ratio, however, is high among the infants with 107 males per 100 females, and even higher among elderly group (65 years and over) with 118 males per females.
 

Source: NSCB, 1995 Census of Population

          Figure II-.   Age-Sex Pyramid, Zamboanga City 

While it defines the volume of demand for various goods and services and supply of human resources, the age-sex structure of a population distribution presents important implications for future population growth, both in terms of immediate and long-term effects. For instance, the fact that 54 percent of the female population of Zamboanga City in 1995 are in their reproductive ages (15-49) years) and that 49 percent of the females 10 years old and over are currently married may indicate a rising birth rate at least in the near future. Moreover, the large number of females at ages 15-19 who are basically at the onst of their childbearing span implies that more births will occur in the next thirty years.

Another determinant, however, of fertility of births as the rate at which women of reproductive ages are marrying. The annual rates of increase in marital union among females 10 years old and over in Zamboanga City are around 3 percent or an additional

2, 370 married women in a year. This is particularly due to the changes in marital status among residents and to a lesser extent, the in-migration of married women. The age-sex structure can also be interpreted in terms of its implications on economic productivity. Basically, Zamboanga City has a young population with a mean age of 23.3 years in 1995.

Population growth, over a period of time, leads to an increase in the working age

population, a prime determinant of the labor force supply. The rapid growth experienced by the city during the period 1970-1980 resulted in significant proportion of the population who are at aged 15 to 25 years. Over all, 60 percent of the total household populations are in their economically productive years. This pool of human resources will be beneficial to the economic expansion of the city.

2.2.1.3  Number of Households and Household Size

Estimates and projections of the number of households are extremely useful in planning especially for mass housing and other specific types of utilities. Ideally, the number of households should grow in proportion to population. In the case of Zamboanga City, the number of households grew at a faster rate than its population – in fact, while, the number of households increased by around 2.5 times during the 20-year period the population grew by 1.9 times between 1975 and 1995. the gap can be attributed to the increased rates of household formation caused by the high marrying rate and household dissolution due to the tendency of inter-barangay or short-distance migration among the people of Zamboanga City.