Following up on what appeared to be a slow March, Facebook traffic boomed again in April across demographic groups in the United States. Young adult age groups contributed the most, with women ages 18 to 25 leading in numeric growth. Overall, the site grew from 113 million to 120 million monthly active users.

Here’s a closer look.

Women between 18 and 25 continue to make up the single largest group of Facebook users nationwide, adding up to more than 17 million today. Young men their ages are the second-largest, with 15.2 million.

Older young adults, between the ages of 26 and 34, continue to be the second largest groups. Women between ages of 35 and 44 or following close behind.

The overall trends played out a little differently this past month, though. Women between 18 and 25 added nearly 1 million more to their ranks, their male counterparts were slightly outpaced by slightly older men and women. Men and women between 34 and 54 also joined in considerable numbers.

But high starting numbers leads to growth rates looking weaker. Relatively speaking, the number of younger women and men on the site didn’t grow by that much.

Meanwhile, the fact that Facebook is more female than male (by 55% to 45% or so), has suggested that there have been men out there who haven’t joined. Especially older men. Many more of them joined last month than we’d been seeing in recent months, leading to a big surge in the growth rate. Men between 55 and 65 grew the most out of any group, at 8.8%.

Some final notes about the data. We get it from Facebook’s advertising tool. It has proven to be in line with third-party measures of Facebook’s traffic, as well with Facebook’s officially disclosed traffic numbers. However, the tool appears to report numbers that are dated by at least several weeks. Therefore, it is possible that these numbers represent at least some part of February and early March, and don’t cover the most recent weeks.

With this context, one can piece together the impact of significant events on the user base. For example, Facebook introduced a home page redesign at the beginning of February. If that resulted in any traffic decreases, they are not clearly visible given the across-the-board growth we’re seeing now.

If you’d like to read more analysis on traffic and growth by demographic, you may also be interested looking at Inside Facebook Gold, our data and analysis membership service focused on the Facebook business ecosystem.