The evolution percentages in the Reports show the percentage rise or decline of a given metric, compared to the previous time period of the same length.
For example, if there is a green percentage of +0.3%, it means the given metric has risen by 0.3% compared to the previous period of the same length.
We show the comparison period for your report at the top of each section, which tells you precisely which time range the evolution is calculated for.
Important:
The fact that it's compared to the previous time period of the same length is important. For example, if we are looking at the period July 16 - August 15, the previous (or preceding) time period is the previous 30 days - in this case, June 15 - July 15. Similarly, when we're looking at July 2018 period (July 1 - July 31; 31 days), the preceding/previous time period for which percentages are calculated is May 31 - June 30.