Lawmakers smile after voting during the 116th Congress and swearing-in ceremony on the floor of the House at the Capitol on Jan. 3. (Brendan Smialowski/AFP)
By Philip Bump
On Thursday, the most heavily female House of Representatives in U.S. history selected a woman as its leader for the next two years, setting a new high-water mark in the gender diversity of the House and Congress as a whole.
That shift is entirely a function of newly elected Democrats — and means that the density of women on Capitol Hill is still less than half of the density of women in the populace.
That said, the past 30 years have seen a big spike in the number of women in the House and the Senate, as data from the Center for American Women and Politics at Rutgers University shows.

(Philip Bump/The Washington Post)
What’s remarkable, though, is how that growth has been driven mostly by the addition of new Democratic women. Since 1989, the number of Republican women in the Senate increased from one to eight; the number of Democratic women in the Senate grew from one to 17. In the House, the difference was much more stark: The number of Democrats grew from 16 to 89 — and, as CNN’s Ryan Stryuk noted on Twitter on Thursday, the number of Republican women didn’t change at all.
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That’s a bit misleading, mind you. In the last Congress, there were 10 more Republican women in the House than there had been 30 years ago. The 2018 midterm elections saw significant erosion in that number.

(Philip Bump/The Washington Post)
The result, as we’ve noted before, is a remarkable divergence in what the two parties' House delegations look like.

(Philip Bump/The Washington Post)
There are twice as many white male House members who are Republicans as Democrats, despite the latter party’s majority. There are seven times as many women who are Democrats as Republicans, seven times as many nonwhite men who are Democrats and 41 times as many women of color who are Democrats.
[Democrats’ generational gap grows with return of Speaker Pelosi and longtime deputies]
Over time, the party split of women on Capitol Hill has increasingly gotten more blue. Eighty years ago, women in the House were about even split between Democrats and Republicans. Now, the percent of female House members who are Republican (12.7 percent) is nearly as low as that figure was in 1973 (12.5 percent), when there were 16 women in the House in total.

(Philip Bump/The Washington Post)
While there are a lot more women in the House, there are slightly fewer women in the House as a percentage of all of the members of that body. A quarter of the Senate is made up of women; 23.4 percent of the House is.

(Philip Bump/The Washington Post)
The scale there is misleading. This is what the density of women in the House and Senate looks like, relative to the rest of each chamber.

(Philip Bump/The Washington Post)
Overall, 23.7 percent of the 535 members of Congress are women, the highest percentage in history and more than twice the density as recently as 22 years ago.
But compared with the population on the whole?

(Philip Bump/The Washington Post)
House of Not-That-Representatives.