Over 18K miles, mine shows 5.3 mi/kWh on average (I never reset the trip meter). If you go by 33.7 kWh/gal of gas, that works out to 179 MPGe.
http://sparkev.blogspot.com/2017/02/spa ... world.html
If you assume 7.5% loss in charging with DCFC, it's 165 MPGe. If you assume 15% loss with L2, it's 152 MPGe. If you assume 20% loss with L1, it's 143 MPGe (4.24 mi/kWh).
However, electricity price has gone up by 12% in past year to $0.20/kWh and gas prices are again down to $2.60/gal. Doing the math, MPG equivalent in $ works out to 55 MPGe$ (with L1). If you factor in eVgo OTG membership for DCFC, average electricity price becomes about $0.30/kWh (I use a lot of DCFC), which makes it equivalent to 42 MPGe$ when using DCFC, 37 MPGe$ when using L1.