Q: Dividing maximum value by minimum value and reporting the difference "in times"

I found this plot good for presenting regional disparities; however, which terms should I use with such figure?

This graph shows differences in mean salary between country regions by study year. Maximum difference for each year is presented, and it is calculated as follows: a region with the highest salary value divided by a region with the lowest salary value. The result of these calculations are presented as "differences in times" (e.g. maximum mean salary difference between regions was 2.5-fold in 2009).

Is it correct to say that this figure shows temporal trends in the maximum differences of mean salary between regions?