Excel Formula for ranking products


I want to score a long list of products based on their volatility of quantity sold in the last 12 months.

for example,

if prod A gets sold 30 each month, then total is 360 for year.
if prod B gets sold in month 3 at 100 and month 4 at 300 then year end is 400 .

prod A is better because it gets sold every month, where as prod B got sold in mar/apr maybe because its a seasonal product yet overall qty performed better than prod A.

so i want to score each product. is there a formula for this and what is the meaning of the result of that formula.

any help is greatly appreciated.