Average of dynamic range based on columns instead of rows

[HJA14]

Dear all,

I would like to get the average of a dynamic range. Normally, the data is located row below row. However, my data set is designed in such a way that each columns represents a data point.
Column A represents the name of the underlying asset. Column B represents the desired average. Column C and beyond represents historical data.
Each row represents an unique asset.
Can someone help me with the formula needed to calculate the average of a dynamic range for each asset? The size of the dynamic range (number of observations) depends on the value in cell A1.

Thanks in advance,

 

[Aladin Akyurek]

In B2 enter and copy down:

=AVERAGE(C2:INDEX(C2:XFD2,MATCH(9.99999999999999E+307,C2:XFD2)))