I have tracked all of my gas purchases for 50 years. For my 2020 Sig, these are the calculated MsPG for each year of ownership, since purchased new in June 2020:
2020: 25.04 (partial yr., covid, drove little)
2021: 25.37
2022: 25.7
2023 (YTD): 26.13.
I retired in late 2021, started...