Not necessarily, you can read them into a single data frame or merge them and then calculate what you want by year.
If you need more specific help with this, please provide a proper REPRoducible EXample (reprex) illustrating your issue.
Not necessarily, you can read them into a single data frame or merge them and then calculate what you want by year.
If you need more specific help with this, please provide a proper REPRoducible EXample (reprex) illustrating your issue.