When I first got the car, which was only four months ago, it started with the stated 47 EV range after a charge. After it adjusted to my driving, it dropped a few miles to 43. I live in a very hilly area, and do half my driving on the freeway, neither of which does do good things for EV ranges. But as of the last month, it's dropped to 37 after an all night charge. Is this normal?? I know batteries do lose some of their charge over time, but I didn't expect it to happen so quickly. I'm leasing the car. I had just about decided that I would keep it, but not I'm leaning the other way.