-33.78% is the change from 977 to 647
Calculation steps:
[( 647 - 977 ) ÷ 977] x 100 = -33.78%
Formula
Percentage change = [(647 - 977) / 977] x 100
Subtract the new number by the original number
647 - 977 = -330
-330 ÷ 977 = -0.33776867963152507
-0.33776867963152507 x 100 = -33.78%