Need help with average formula

I need some help formatting an "average" formula for excel 2010 please

I have 3 rows (B8 to M8, B9 to M9 and B10 to M10) for the months of the year that I need to get an average for. There are 36 cells that may or may not have dollar amounts in them and I need to get an average for all those cells that have dollar amounts in them. So if 25 cells have figures in them I need the average for those 25 cells not all 36. Cells may have 20 of them with dollar amounts or 32 etc. so the average needs to be calculated without the empty cells. How do it accomplish this?
Thanks in advance for any help.
Gene