2D Array Row Manipulation

After the following code segment is executed, what are the values in the data array?

int [][] data = {
    {3, 6, 9, 12}, 
    {15, 18, 21, 24}, 
    {27, 30, 33, 36}
};

for (int r = data.length - 1; r > 0; r--)
{
    for (int c = 0; c < data[r].length; c++)
    {
        data[r - 1][c] = data[r][c];
    }
}