"Arianespace milestones during the 2012 Spaceport mission activity included Ariane 5’s heaviest-ever payload: the ATV Edoardo Amaldi, weighing more than 20,000 kg. on its flight in March; along with the 50th consecutive success for this heavy-lift workhorse launcher, achieved in August – subsequently increasing to 53 by year-end, underscoring a reliability level that a benchmark in the commercial launch services sector."
Source: From an Arianespace report in which the entity notes that it achieved an a record-breaking year of activity during 2012, employing its complete launcher family to perform 10 total flights from the Spaceport in French Guiana along with a Soyuz mission from Kazakhstan’s Baikonur Cosmodrome.