Serial Numbers Based Upon Another Cell

I have a spreadsheet with owner and tenant information, along with their vehicle information. In the column that indicates if they are an owner, I have used data validation to limit the entry to either "O" or "T" that I want to incorporate into the serial number along with the current year. So, it should read something like "O-2019-01" or "T-2019-01" and increase by one for each entry and be static if the list changes, for example, by filtering. I cannot seem to locate exactly the right information to accomplish what I am trying to accomplish.