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Methods-In-person interviews using laptop computers. Among the total sample of males and females 15-44 were 1,150 females and 1,121 males aged 15-19. Response rate for teenagers was 81 percent.

Objective-This report presents national estimates of contraceptive use and method choice based on the 1982, 1995, and 2002. It also presents data on where women obtained family planning and medical services, and some of the services that they received.Methods-Data were collected through in-person interviews with 12,571 men and women 15-44 years of age in the civilian noninstitutional population of the United States in 2002. This report is based on the sample of 7,643 women interviewed in 2002. The response rate for women in the study was about 80 percent.Results-The leading method of contraception in the United States in 2002 was the oral contraceptive pill, used by 11.6 million women; the second leading method was female sterilization, used by 10.3 million women. The condom was the third-leading method, used by about 9 million women and their partners. The condom is the leading method at first intercourse; the pill is the leading method among women under 30; and female sterilization is the leading method among women 35 and older.

In the last 2 decades, the United States has seen an increase in childlessness and first births at older ages. Using the National Survey of Family Growth, we focus on women aged 35 – 44 who are voluntarily childless (expect no children and are fecund or contraceptively sterile). We compare these women to those who are involuntarily childless (fecundity impaired) and to those who are temporarily childless (expect children). Voluntary childlessness grew from 1982 (5%) to 1988 (8%), was stable up to 1995 (9%), and fell slightly in 2002 (7%). Voluntarily childless women have the highest income, prior work experience, and lowest religiosity compared to other women. This has been true since 1982, the earliest time point examined.

Study of the electrical conductances of a series of ultrathin Bi films as a function of increasing thickness has revealed behavior which can be correlated with the onset of superconductivity, even in the insulating state. The conductances of these films scale empirically with a single parameter which falls to zero when the films become superconductive. These observations suggest a direct transition between insulating and superconducting behavior. This transition occurs at a normal-state sheet resistance close to the quantum resistance for pairs, R q =h/4e 2 .