R apply and get values from previous row

I'd like to use the previous row value for a calculation involving the current row. The matrix looks something like: ``` A B [1,] 1 2 [2,] 2 3 [3,] 3 4 [4,] 4 5 [5,] 5 6 ``` I want to do the following operation: `(cell[i]/cell[i-1])-1`, essentially calculating the % change (-1 to 1) from the current row to the previous (excluding the first row). The output should look like: ``` C D [1,] NA NA [2,] 1.0 0.5 [3,] 0.5 0.33 [4,] 0.33 0.25 [5,] 0.25 0.20 ``` This can be accomplished easily using for-loops, but I am working with large data sets so I would like to use apply (or other inbuilt functions) for performance and cleaner code. So far I've come up with: ``` test.perc <- sapply(test, function(x,y) x-x[y]) ``` But it's not working. Any ideas? Thanks.