For the season, the team retained both Hamilton and Rosberg. At the 2015 Russian Grand Prix the team won their second Constructors' Championship as a works team and Hamilton won his second consecutive Drivers' Championship at the 2015 United States Grand Prix, finishing 59 points ahead of Rosberg. Mercedes continued their domination in this second year of the V6 turbo era, improving on their impressive numbers from 2014 with 18 pole positions, 16 wins and 12 1–2's in 19 races. Of their 16 race victories, the average winning margin to the nearest non-Mercedes competitor was 19.7 seconds, down from 23.2 seconds in 2014.