For any who might be curious, I ran an exponential analysis, and for :

DSLR, it's an annual decrease of 11.87 % and will be
4,330,000 in 2023

Mirrorless, it's an annual increase of 3.027 % and will be
4,351,300 in 2023

Looks to be about equal by 2023.

Use any of this at your own risk.