((y2 - y1) / y1)*100 = your percent change. y1 is the original value, and y2 is the value it changed to.

Using the formula for percentage change, and following the order of operations

- Subtract (9.49 - 2.50) which gives you: 6.99
- Divide 6.99 / 2.50 which gives you: 2.7960000000
- Multiply 2.7960000000 * 100 = 279.6