A proportion box can be used to solve this problem. First, we need to compute the difference or change in the original amount of visitors Alec had (in February) and the new amount of visitors (in March).
1,525 - 1, 385 = 140
We place this amount (140) in the top left of our box, and we place the original amount (1,525) in the bottom left of our box. We are looking for the percentage decrease, so that box in the upper right will stay empty. The number 100 always goes in the bottom right of our percent proportion box.
(The attached image will show an example of how to set this up).
Our last step is to cross multiply and divide.
140 x 100 = 14,000
14,000 ÷ 1,525 = 9.18
So, the percentage decrease of the number of visitors to Alec's website from February to March was 9.18%.