N evol corresponds to the change in% between the measurement of a period in year N and its equivalent in N-1
N evol = N / (N-1)
Certain evolutions, like distributions, are calculated in delta (evolution points) and not in percentage of evolution.
In this case, we subtract N and N-1.
In evolution modules, like Sales Evolution, the percentage of the current year N Evol is the result of the YTD N vs YTD N-1, while the N Trend is calculated in Year N vs Year N-1 (see screenshot below)
Similarly, the evolution of a Current Qtr (therefore a QTD) in Sales Evolution, will be calculated vs the same months in the corresponding QTR N-1 (therefore the QTD N-1).