Iowa is among the states with the lowest rates of increase in the number of women-owned businesses between 1997 and 2011, according to the American Express OPEN State of Women-Owned Businesses report released last week.

    The number of women-owned firms in the state has increased by an estimated 20.1 percent, which ranked 49th among of the 50 states plus Washington, D.C. That compared with a national average of 50 percent. Iowa ranks last in revenue growth, with an estimated 3.1 percent decline, and employment in women-owned businesses has gone down by 19.3 percent.

    The report uses data from the U.S. Census Bureau’s Survey of Business Owners, which is conducted every five years and was last done in 2007, along with the group’s own projections for 2011.