Estimating from the Archival Census and Education Needs Survey in the United States (available in full as pdf from http://www2.archivists.org/initiatives/acensus-archival-census-education-needs-survey-in-the-united-states), one finds that the profession in 2005 was 65 % female and 35% male. This represents a reversal of the profession’s profile in 1956 when SAA members were surveyed by Ernst Posner. Then, the profession was 67 percent male and 33 percent female. In 1982 the profession was 46 percent male and 54 percent female.
“Archival Census and Education Needs Survey in the United States,” American Archivist, vol. 69, no. 2 (Fall/Winter 2006): 294-618.