In January 2024, there were 12,218 submissions to the Newgrounds Audio Portal, by far the most in the Portal's 21-year history. This is actually quite easy to verify: the first submission of February was @Urielthepro's "February", and the first one of January that wasn't subsequently taken down was @IvySnyder's "24-1-1-1-1" (the true first of the month - this one - was taken down sometime in January). Just subtract the audio IDs from each other, and add 1 for the missing "true first," and you come up with 12,218.
And yes, I figure out this number every month because I'm an absolutely UNWIELDY stat nerd. The previous record was 11,646 submissions in June 2021. Here's a chart of the number of Audio Portal submissions every month since February 2003:
TL;DR: I'm a huge dweeb and the AP is as popular as ever. :)