To find the percentage difference between two numbers, we first need to calculate the absolute difference between them. In this case, the absolute difference between 135 and 165 is 30.

Next, we need to find the average of the two numbers. The average of 135 and 165 is (135+165)/2 = 150.

Now, we can calculate the percentage difference by dividing the absolute difference by the average and multiplying by 100. So, the percentage difference between 135 and 165 is (30/150) x 100 = 20%.

Therefore, the percentage difference between 135 and 165 is 20%. This means that 165 is 20% more than 135.