Fewer and fewer women are making up the American IT workforce, declining by 18.5% in eight years.

The percentage of women in the IT labor force fell last year to 32.4% from a high of 41% in 1996, according to new research from the Information Technology Association of America (ITAA), an industry trade group. As a comparison, the percentage of women in the overall workforce remained virtually unchanged in that same period, at roughly 46%.

In addition, most racial minorities remain significantly underrepresented in the U.S. IT workforce, according to the report, Untapped Talent: Diversity, Competition, And America's High-Tech Future, which ITAA released Wednesday.

The underrepresentation of women and minorities in IT isn't healthy for the United States as it competes in the global marketplace, ITAA president Harris Miller says in a statement accompanying the report. "America is competing in the global economy with one hand tied behind her back," Miller says. "With competitors like China, India, and Western Europe on our heels, we can ill afford to miss out on anyone with the right aptitude, skills, and motivation to succeed in technical fields."

The ITAA study attributes the falloff of women in the IT labor force to the fact that one out of every three women in IT held administrative jobs that have experienced significant overall declines in recent years. When those categories are excluded from the analysis, the percentage of women in IT drops from 32.4% to 24.9%. Still, the report says that figure represents no progress in the number of women in the professional or management ranks from the relatively low 25.4% mark achieved in 2002.

Among racial groups, ITAA says Hispanics were the most underrepresented in the IT workforce during 2004. Hispanics make up 12.9% of the U.S. workforce but represent a mere 6.4% of IT workers. That figure represents a slight increase from 5.3% in 1996. African-Americans in the IT workforce were underrepresented by 22.4%, when compared with their representation in the overall labor force. Even whites were underrepresented by 6.6%. Americans of Asian descent, however, are overrepresented in the IT labor force, when compared with the overall workforce, by nearly 200%.

The study also found that the U.S. IT workforce is getting older. The median age of the IT workforce, 39.7 years, is approaching that of the overall workforce, 40.5 years, gaining 2.1 years between 2000 and 2004. The median age of the overall workforce rose 1.1 years during that four-year period.

Little progress has been made in the perceived barriers for women and minorities since ITAA issued its last diversity study two years ago. ITAA says those hurdles include societal barriers, such as stereotypes that women and certain minorities aren't skilled in math and sciences; a lack of mentoring and role models in leadership positions; and negative perceptions of IT work. In addition, ITAA surmises, a reduction in flexible work arrangements following the dot-com boom might also account for fewer women in the IT workforce.

ITAA based its findings on an analysis of data from the U.S. Labor Department's Bureau of Labor Statistics Current Population Surveys, the same data used to determine the monthly unemployment rate. The annual numbers in its report represent an average of the monthly figures.