Q:

What is the difference between ratio change vs percent change ? (finance question)

I had a question which asked us to calculate the percentage decrease in operating income between years 2012-2013 and wanted us to predict the decrease rate for the next year. When I calculated the %change, I used the typical formula of (2013 value/2012 value)-1 *100. However, the feedback in the textbook had us only calculate the "ratio of operating income which is 2013 value/2012 value" without subtracting 1. 
Why is this? 
Now this may seem like a basic question, but it totally changed the final answer. 

A:

The  ratio of $V'$ to $V$ is $V'/V.$ The   change  from $V$ to $V'$ is $V'-V.$ The proportionate change in $V,$ from $V$ to $V',$ is $\frac {V'}{V}-1=\frac {V'-V}{V}.$  The percent change in $V,$ from $V$ to $V'$, is $(\frac {V'}{V}-1)(100).$
The execrable phrase "times more than" became popular because of its widespread use by broadcasters and other journalists who do not understand any of this.

