fall off
US /fɔːl ɔːf/
UK /fɔːl ɔːf/

1.
diminuer, baisser
to decrease in quantity or quality; to decline
:
•
Sales tend to fall off during the winter months.
Les ventes ont tendance à diminuer pendant les mois d'hiver.
•
His performance has started to fall off recently.
Ses performances ont commencé à diminuer récemment.