Answer: industry average
Explanation: In simple words, industry average refers to the data that is presented by some institution depicting the performance of all the firms in the industry as a whole with respect to factors like profitability, leverages and growth.
To compare a company's performance over time it is best to compare it with industry average as usually it is difficult to find a competitor whose market conditions are similar to one another.
Thus, for over the period performance analysis it is best to use industry average.