Well, for a 5 year period, I'd agree with 2008-2012. Those were the years of maximum contention and distribution among the Big 3. 2008 had Djokovic winning AO, Nadal taking the French, Nadal over Fed in the classic Wimby match, and Federer over Murray at the USO. 2012 had the classic Djokovic beating Nadal for the AO match, Nadal over Djokovic at the French, Fed over Murray at Wimbledon, and Murray over Djokovic at USO.