-15.05% is the change from 977 to 830
Calculation steps:
[( 830 - 977 ) ÷ 977] x 100 = -15.05%
Formula
Percentage change = [(830 - 977) / 977] x 100
Subtract the new number by the original number
830 - 977 = -147
-147 ÷ 977 = -0.150460593654043
-0.150460593654043 x 100 = -15.05%