One Iowa-based company made this year’s nationwide list of the top 30 companies for executive women, according to a survey from the National Association for Female Executives. Association president Betty Spence says Principal Financial Group is doing an “extraordinary” job of hiring and promoting women.The number of women in senior management has more than tripled in the past five years while the number of female department and division heads has risen 35-percent and the number of women managers has gone up 59-percent. Spence says Principal, based in Des Moines, is also a leader in the way it handles off-time via the Family Medical Leave Act. Principal offers its workers 12 extra weeks over what they get with the federal program, and workers can return part-time and get full benefits, which Spence says is very unusual. While Principal didn’t make the top ten, the company is listed among the top 30, which are not ranked numerically.She explains a little about how the top companies for women executives are singled out. They assess the number of women versus men who are “in the pipeline” for top positions as well as women who’ve already made it onto executive row. This is the third year in a row Principal has made the list, joining other companies like Avon, Scholastic, Liz Claiborne, Wellpoint, Hewlett-Packard, Kraft Foods, The New York Times Company and I-B-M.