The decline in birth rates over the past few decades has lowered population growth rates in developing countries despite a continuing decline in death rates. Population growth is even slower in developed countries (Figure 3.4). Stabilizing birth rates and increasing death rates (the latter being a result of aging populations; see Chapter 8) have already led to a natural population decrease in Italy and Germany. Japan and Spain are expected to follow soon (see birth rates and death rates in Data Table 1).

Over the past 30 years the worldwide population growth rate fell from more than 2.0 percent to 1.5 percent a year, and experts expect this trend to continue. But in absolute numbers the world's population is growing faster than ever before- by about 230,000 people a day in mid-1995. This is happening because of the larger than ever population base. In 1995 there were about 5.7 billion people on earth, almost twice as many as in 1970. The next 35 years are projected to add another 2.5 billion people- 90 percent of them in developing countries. The share of developing countries in the world population is expected to increase from 84 percent to 88 percent.

In the short run, rapid population growth in poor countries leads to lower GNP per capita, allowing fewer resources to be invested in each person's human capital- the key to increasing labor productivity. But in the long run, provided that labor productivity does in fact increase, having more workers could contribute to the economic strength of developing countries.

The formerly socialist countries of Central and Eastern Europe present a major exception to the broad similarity of demographic trends in developed and developing countries. The rapid decline in death rates that occurred in the 1950s and 1960s slowed down in the 1970s and 1980s. In the 1990s death rates actually increased in Russia and some other transition countries, including Belarus, Bulgaria, Estonia, Latvia, Lithuania, Moldova, Romania, and Ukraine. In 1995 the death rate in Russia equaled the average for Sub-Saharan Africa-15 deaths per 1,000 people- while the average death rate for developing countries was 9 per 1,000 and for developed countries was 8 per 1,000.

This dramatic and historically unprecedented reversal in mortality trends is primarily explained by higher adult male mortality: among older men mainly because of the increase in cardiovascular disease, among younger men because of more accidents, suicides, and murders. Many of these factors can be related to substance abuse- heavy drinking and smoking, which in turn can be linked to worsening living conditions and the greater uncertainty and stress that have accompanied the transition. But rapid economic reforms have not necessarily been detrimental to people's health in all transition countries. For example, in the Czech Republic the death rate has continued to decline (Figure 3.4), while in Hungary and Poland it has held steady.

Birth rates in the transition countries of Europe have dropped sharply in the past 5-10 years. The reasons for that drop are different from those in most developing countries: they are believed to be closely associated with a lower quality of life caused by the social and economic crisis of transition. As a result fertility rates in these countries are now far below the "replacement level" (equaling slightly more than two children per family) and lower than those in most developed countries (see Figure 3.3).

Because of these unusual demographic trends- increasing death rates combined with dropping birth rates- many of the transition countries of Europe (for example, Russia and Latvia, see Figure 3.5) have experienced natural decreases in population.