FIGURE D-2 U.S.-trained Ph.D.s by employment status and major field, 2001, 2003, and 2006 (thousands).

SOURCE: Data extracted from National Science Foundation Survey of Doctorate Recipients 2001, 2003, and 2006.

FIGURE D-3 Sex ratio in the U.S.-trained workforce by major field and survey year, 1995-2006.

SOURCE: Data extracted from National Science Foundation Survey of Doctorate Recipients, 1995-2006.

As the sex ratio fell, female scientists apparently became more likely to find scientific employment. In the biomedical field, 85 percent of male scientists were employed in science in 2006, but only 79 percent of female scientists were so employed. In the other two fields, employment in science was almost equally likely for each gender, which was not true in the past (Figure D-4). Female scientists are more likely than males, however, to be out of the labor force. (Those out of the labor force but not retired are counted, for current purposes, as being in the workforce, because one assumes, for projection purposes, that they could readily return to employment.) The numbers are small—about 5,000 in the three fields combined—but the proportion among women in 2006 was five to nine times the proportion among men.

The age of the labor force has also been changing gradually. The median age in 2006 was considerably lower among biomedical scientists, at 46.9 years, than in the other two