Across all platforms
Rocket League references are just about everywhere at this point — it’s creeped its way into pop culture, and isn’t going anywhere.
And a recent stat from developer Psyonix (which I still confuse withPsygnosis, RIP) backs that up — since its debut on PC in July of 2015, it has hosted more than one billion games. Other stats include a 25 million playerbase in which 50% of them play competitive modes, with 33% in casual gametypes, 11% in “other” modes, and 6% playing privately.
I haven’t played in quite a while (unless you count the OverwatchLucioball homage).