-80% is the change from 545 to 109
Calculation steps:
[( 109 - 545 ) ÷ 545] x 100 = -80%
Formula
Percentage change = [(109 - 545) / 545] x 100
Subtract the new number by the original number
109 - 545 = -436
-436 ÷ 545 = -0.8
-0.8 x 100 = -80%
Example