I've also made a metric which should measure the degree to which your cohort matters in terms of how much you can expect to make per post. The lower the number, the less influence which cohort you are in has on your author rewards. We can see that this was very high in January 2018 (height of Steem bubble), but has gradually dropped off to where it is now.
What this shows is that it is much easier to break in and start earning rewards on #Hive today than it was back in the days of #Steem.
A better chart for the same purpose:
In laymen's terms, this shows how much a user who has registered within the same year can expect to earn for their posts compared to the average user who registered in a previous year.
At the lowest point (height of Steem bubble), this was a mere 11%. It has gotten substantially better since hard fork, settling around 60%.