My commute is about 14 miles each way, but the majority of the way in is uphill - I tend to average 45 in the morning and 52-54 on the way back. however, for the first couple of miles the average is only in the 20's while the engine warms up.
If your journeys are only 2 miles then you will get pretty poor economy. Best I achieved so far was 62 in heavy traffic, M4 on a Friday afternoon