Spreadsheet with a percentage of the number of zero count how

In the spreadsheet to calculate the two-digit percentage, but there are a number is 0, such as A1 is 0, B1 is 2, I C1, enter = B1/A1 when the information is wrong, how do I ask? There , has been considered from the C1 to C20, only one by one calculation, there is no simple way?

Do you mean you A1 always be the denominator? C1 = IF (A $ 1 = 0, “”, B1 / A $ 1) copy down, on the line.

1, A1 always be the denominator will always be wrong 2, A2 is not 0, which is the denominator