Not raw numbers, but the percentages of market share by desktop platform are listed here: https://gs.statcounter.com/os-market-share/desktop/united-st... Mac is supposedly at 29.62%
It's good to keep that last bit in mind when looking at these graphs. It's technically possible for users to have increased usage on a platform AND for more users to have started to use the platform but the platforms usage share goes down. This is because more users are present over time and users can browse on more than one device more than once per day.