Say what you want about the United States of America, but we don’t have the world’s lowest percentage of women in the national legislature.
Here are the countries with at least 5 million people in 2013, arrayed by income and percentage of women in parliament (click to enlarge)*:
Source: My figure form http://wdi.worldbank.org
On the plus side, the USA leads the world in per capita income among countries with fewer than 19 percent women in its national legislature (except for the United Arab Emirates.)
* Note: Rwanda, with per-capita income of $1,430, has 64% women in parliament, but I didn’t include it because expanding the scale that far shrank the rest of the graph too much. Also note Canada is accidentally mislabeled as Cameroon.