LuAnne Thompson of the University of Washington has been working with data on the number of women at various career stages in physical oceanography. The data comes from NSF surveys, MPOWIR data, and UW surveys.
Slides from a recent talk are available here: PO_Women-Thompson
Over the last ten years, only 1 in 10 female PhDs have ended up in a tenure track position compared with 1 in 4 males. In the pre-1996 pool, 1 in 5 women have tenure track positions compared with 1 in 4 men. Either women are less likely to obtain a tenure-track position than they used to be, or on average it takes women longer to get a tenure-track position. Women seem to be increasingly going into government, industry, research staff/instructor, and other positions.