it went from 8 to 6.5, namely 8 - 6.5 = 1.5.
if we take the 8 to be the 100%, what is 1.5 off of it in percentage?
well, we can round that up to 18.8%, however since it's a subtraction from the board, we can say is -18.8%, a negative percent, because is a percent that was taken out of it.