-99.85% is the change from 670 to 1
Calculation steps:
[( 1 - 670 ) ÷ 670] x 100 = -99.85%
Formula
Percentage change = [(1 - 670) / 670] x 100
Subtract the new number by the original number
1 - 670 = -669
-669 ÷ 670 = -0.9985074626865672
-0.9985074626865672 x 100 = -99.85%