2012 was a record election cycle for female candidates at the ballot box, as voters ushered the largest number of women ever into Congress (20 in the Senate and more than 70 in the House).

Compared the lead-up to the 1990 election, when just 31 women were serving on Capitol Hill, that's quite a jump, reflecting steady growth spanning nearly three decades. But when it comes to political donors, the gap between men and women has not moved as much.

We know this all thanks to a fascinating study from Sarah Bryner and Doug Weber at the Center For Responsive Politics. They tracked various data on female candidates and donors in recent decades, and made some striking findings. The most notable among them:

* The number of women who have won House races has steadily been rising, as the following chart from the study shows. In addition, the gap between the number of Democratic women and Republican women who've won has grown. Women make up a much larger share of the Democratic general election candidate pool than they did in 1990, whereas growth has been more modest on the GOP side.

* When it comes to female campaign donors, there's been less momentum in terms of increasing influence. In the 1990 cycle, 22 percent of all itemized federal contributions came from women, not far off the 25 percent so far this cycle. What's more, 11 of the top 100 contributors in 2012 were women, a decline from the 21 in the same category in 1990.

* Female Democratic candidates for federal office get the most money from women donors, as a percentage of the total money they give. And overall, Democrats have consistently received between 50 and 60 percent of the total contributions from women. The exception: 1996, when Democratic candidates got just under half.

(Note: The report looks at candidates who gave more than $200.)