I don't have my logs with me but...
At 70/208 - I got 48 Ideal Miles per hour (McDonald's in Barstow)
At 40/240 - I get about 30 Ideal Miles per hour (at home)
At 12/120 - I get about 3+ Ideal Miles Per hour (at home)
Also, I've tracked Kwh from the grid versus what gets in the battery and I lose on average 25%. I read somewhere the Model S claims 93% effeciency rate but my Roadster is about 75%.