-16.62% is the change from 770 to 642
Calculation steps:
[( 642 - 770 ) ÷ 770] x 100 = -16.62%
Formula
Percentage change = [(642 - 770) / 770] x 100
Subtract the new number by the original number
642 - 770 = -128
-128 ÷ 770 = -0.16623376623376623
-0.16623376623376623 x 100 = -16.62%