Translate the following English sentence to French:
"According to the statistics, the incidence of a 15-minute delay has risen from 12.7% in 1991 to 30.3% in 1999 and is still rising."
Selon les statistiques, la fréquence des retards de 15 minute a augmenté de 12,7 % en 1991 à 30,3 % en 1999 et continue à augmenter.