I probably see on average 1-2 per day. Generally it's a Prius, and occassionally I see the RX400h that lives in my area, and I've seen a total of 2 Hylander Hybrids. I often see other FEHs, and the only HCH/HCHII that I've seen is my Mum's, but she doesn't live in the area so I don't see it often.

The most I've seen in one day, was probably the 8-10 FEHs that were on a truck on the highway being delivered... I wish I had the camera in the car for that... would have made a nice picture.