-37.47% is the change from 830 to 519
Calculation steps:
[( 519 - 830 ) ÷ 830] x 100 = -37.47%
Formula
Percentage change = [(519 - 830) / 830] x 100
Subtract the new number by the original number
519 - 830 = -311
-311 ÷ 830 = -0.3746987951807229
-0.3746987951807229 x 100 = -37.47%