-15.5% is the change from 645 to 545
Calculation steps:
[( 545 - 645 ) ÷ 645] x 100 = -15.5%
Formula
Percentage change = [(545 - 645) / 645] x 100
Subtract the new number by the original number
545 - 645 = -100
-100 ÷ 645 = -0.15503875968992248
-0.15503875968992248 x 100 = -15.5%