translate English to French: The analysis revealed that, based on an industry wide average, non-participants were able to increase their gross incomes by about 55% over and above what their incomes would have been had the program not existed.
L'analyse a révélé que, d'après une moyenne s'appliquant à l'ensemble de l'industrie, les non-participants ont vu leur revenu brut augmenter d'environ 55 %, abstraction faite de leur revenu si le programme n'aurait pas existé.