-1.31% is the change from 990 to 977
Calculation steps:
[( 977 - 990 ) ÷ 990] x 100 = -1.31%
Formula
Percentage change = [(977 - 990) / 990] x 100
Subtract the new number by the original number
977 - 990 = -13
-13 ÷ 990 = -0.013131313131313131
-0.013131313131313131 x 100 = -1.31%