Population doubling time: looking backward.

PIP: Using population doubling time (the number of years it would take a population to double assuming a constant growth rate), to look backward to examine when today's population totals were half their current size reveals a striking divergence in patterns of change in Africa, Latin America, and Asia. In Africa, for example, the population has doubled from 1970 to 1994 and is expected to double again in the next 24 years. Ethiopia has doubled since 1967 and will double again in 23 years. Egypt has doubled since 1964 and will double again in 31 years at its current growth rate of 2.3%. Latin America doubled its population from 1864 to 1994 and will do so again in 38 years. Mexico will need 33 years to double, but Brazil will take 43 years. In Asia, the population doubled in 33 years and will probably double again in 39 years. Japan, however, doubled in 66 years and will not double again for 183 years. Bangladesh, on the other hand, has a current doubling time of 29 years. To understand the effect of fertility change on doubling time, it is instructive to consider that the population of the world was half its current size in 1957 with a growth rate of 1.85% which would have resulted in 40 million fewer people today were it not for a temporary boast in growth rate to 2.1% in the late 1960s. Short doubling times are expected to continue in developing countries at least until the beginning of the 21st century.^ieng

State-by-state data on crime, AIDS, aging.

PIP: The United States Population Data Sheet (Population Reference Bureau, 1994), 11th edition, lists information by state concerning crime rate, acquired immunodeficiency syndrome (AIDS), demographic aging, and expected population growth. Crime rates for 1992 were highest in the District of Columbia (11,407 serious crimes--murder, aggravated assault, burglary, arson, and rape--per 100,000), Florida (8358), Texas (7085), Arizona (7029), and California (6680). They were lowest in West Virginia (2610), North Dakota (2903), South Dakota (2999), New Hampshire (3081), and Kentucky (3324). The states with the highest crime rates were more urban. The rates of new, reported AIDS cases, which have more than doubled because of changes in the definition of AIDS by the Centers for Disease Control and Prevention (1993), range from 274 per 100,000 in the District of Columbia, 96.0 in New York, 79.9 in Florida, 69.0 in New Jersey, and 59.9 in California to 1.7 in North Dakota. The lowest rates are found in Montana, South Dakota, West Virginia, and Idaho. The rate for the United States is 40.1. Age structures are dramatically different among the states. 4.3% of the population of Alaska (the youngest state) are age 65 or over; 18.6% of Florida (the oldest state) are. The ratio of births to deaths (another measurement of population aging) in 1993, for the United States, was 182/100. West Virginia, Pennsylvania, Florida, Arkansas, and Maine have ratios less than 140/100. Alaska, Utah, Hawaii, California, and Texas rank above 240/100. Overall, the population of the United States is expected to grow 25% by the year 2020 (Census Bureau). Growth is expected to be most heavy in the Sunbelt. The population in the West is projected to grow by 50%; that in the South should grow by almost 33%. California, Nevada, Washington, and Hawaii are projected to grow by more than 50%. West Virginia, New York, Pennsylvania, Ohio, Iowa, Rhode Island, Michigan, Connecticut, and the District of Columbia, the slowest growing states, are projected to grow by no more than 10%.^ieng