The World Bank and CIESIN (Consortium for International Earth Science Information Network) have placed this material (along with Social Trends in Developing Economies) on the Internet as part of an experiment. This searchable data set spans 170 different economies with as many as 94 indicators covering a very wide variety of health, demographic, and economic information. Its annual data ranges from 1965 to 1994. The search mechanism makes very nice use of the web. The only vaguely tricky part is finding the entry to it on their page.
http://www.ciesin.org/IC/wbank/sid-home.html