TMC

I also posted this in another thread but it's more appropriate here. I bought my energi about 3 months ago with 35k and in the beginning I would see 20 mile range on the display after charging. The car now has about 40k. After being on vacation and the car sitting for that week it shows only 15 or 16 on the display. It's been that way for the week we've been back. Is reduced range and battery degradation a warranty issue?