FINALLY: Google just revealed YouTube's ad revenue, 14 years after acquiring it, and the video site brought in $15 billion last year

Google revealed that YouTube's advertising revenue totalled $15 billion in 2019, ending a longtime policy of keeping the video site's financials under wraps.

The results, which Google released with its fourth-quarter earnings report on Monday, come 14 years after Google bought YouTube in a $1.65 billion acquisition.

Ads on the video site now comprise about 9% of Google-parent company Alphabet's overall revenue, which totalled $162 billion last year.

Even as YouTube has grown into a massive site, its ad revenue continues to grow at a healthy pace, increasing roughly 36% in 2019. That's a much faster pace than Google's overall ad revenue, including its search ads business, which grew by only 16% year-over-year in 2019.