Lower watt-hour/mile (or km) over time for old Model S cars?

[ORB]

Hello,

Has the overall watt-hour/mile (or km) figure for old Model S cars decreased over time (since 2012) due to Tesla software updates aimed at improving driving energy efficiency? If the efficiency improved, what is the consensus of TMC owners of old Model S cars as to how much? Might Elon have stated any specific driving efficiency gains that are applicable to all Model S cars?

Thanks in advance!
Oliver Barrett