Compound quarterly earnings rate

I use Excel to manage my investments. Each quarter I calculate the percentage return. I also to calculate my average return over longer periods, say 4 quarters or 12 quarters. Currently I do this by multiplying each quarterly return together , say quarters 1 thru 12, then I take the 1/3rd root of that calculation. This gives me an average annual return over 12 quarters or 3 years. Not elegantly stated, here's an example:
=((1+M68)*(1+M67)*(1+M66)*(1+M65)*(1+M64)*(1+M63)*(1+M62)*(1+M61)*(1+M60)*(1+M59)*(1+M58)*(1+M57))^(1/3)-1

Is there a better way to accomplish this task?