The new rules introduced into Formula One to encourage overtaking in 2011 appear to have borne fruit with the number of passes after nine rounds of the championship already more than for the whole of the 2010 season. Sources within the Mercedes team told AFP that official statistics show 623 instances of overtaking so far this season, more than the 547 from 19 races in 2010 and 244 from 17 races in 2009. "If the trend continues, it will reach 1,200 by the end of the year," said one of the team. The big jump from 2009 to 2010 was caused by the arrival of three new teams, Hispania, Virgin and Team Lotus, who stuggled to keep pace and were consistently lapped. This year's rise has been attributed in part to the rise in the number of teams from 10 to 12 as well as the introduction of an adjustable rear wing that creates the drag reduction system (DRS) which provides a higher top speed and tyres that degrade faster than they did last year. "Of the 623 overtakings, 175 have been at the expense of three stables at the back of the grid and 43 between teammates. Some 180 were made using the DRS (29 percent) and 225 free," said Mercedes. The Canadian Grand Prix in Montreal saw the most overtaking manoevres with 136 while Istanbul (123) and Shanghai (97) also provided plenty of excitement. The races that scored least well were Monaco (22), Silverstone (29) and Melbourne (30)