Return On Investment
According to Investopedia (http://www.investopedia.com/terms/r/returnoninvestment.asp#ixzz1bcKSKpx9)::
"A performance measure used to evaluate the efficiency of an investment or to compare the efficiency of a number of different investments. To calculate ROI, the benefit (return) of an investment is divided by the cost of the investment; the result is expressed as a percentage or a ratio.
The Return On Investment formula:
In the above formula "gains from investment", refers to the proceeds obtained from selling the investment of interest."