Analysis of World Fertility Survey data from five countries--Colombia, Costa Rica, Korea, Malaysia and Nepal--shows that the availability of contraceptive services and supplies is a major determinant of use. In Nepal, where few women know where to obtain supplies, only two percent are contracepting. In Costa Rica, where almost all married women know an outlet nearby, 53 percent use effective methods.
The unmet need for family planning services is remarkably constant across all five countries because of the interaction of fertility intentions and fertility control: as more women use contraception, more of them want fewer children.