Formula to show Average of the last 'N' values in a row.

Hi,

I need a formula to show the Average of the last 'N' values in a row. The row will be dynamically expanding. It is a database where the first column is a list of names. Each successive column represents an event where every person might be assigned a number. I want a formula to show for each person the average of their last 'N' non-blank values.

Can anyone help me out?

Edit: In the sample workbook what is needed is a formula in D2 to show the average of the last "N" values in the row starting from E2.