-63.25% is the change from 830 to 305
Calculation steps:
[( 305 - 830 ) ÷ 830] x 100 = -63.25%
Formula
Percentage change = [(305 - 830) / 830] x 100
Subtract the new number by the original number
305 - 830 = -525
-525 ÷ 830 = -0.6325301204819277
-0.6325301204819277 x 100 = -63.25%