Here's another post of mine from Murray's World back from 2012. I didn't take 2013 because we weren't into that just yet, but now that we know he's won 1 title this year and that not being on clay, the % almost remains the same - 12.98% if you want to be very specific.
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Here's a look at Federer's overall results on clay. Turned pro in 1998 but his first title came on indoors (carpet) in Milan in 2001 where he beat Julien Boutter in the final.
2001: No title
2002: title: 1 (Hamburg Masters)
Beat Safin
2003: title 1 (Munich 250)
Beat Nieminen
2004: 2 titles (Gstaad 250, Hamburg)
Beat Igor in Gstaad
Beat Coria in Hamburg
2005: 1 title (Hamburg)
Beat Gasquet
2006: No title
2007: 1 title (Hamburg)
Beat Nadal
2008: 1 title (Estoril – 250)
Beat Davydenko
2009: 2 (RG, Madrid Masters)
Beat Soderling at RG
Beat Nadal (Nadal was far too tired after beating Nole in a 3 grueling sets in the semi)
2010: No title
2011: No title
2012: 1 (Madrid Masters – blue clay - both Nadal and Nole bombed out early due to sudden surface change)
Beat Berydych
So to sum it up, Federer has won 10 clay titles in total in 13 years – 1 RG, 4 Hamburg Masters, 2 Madrid Masters and 3 250 events (Munich, Gstaad and Estoril). That’s 13% of his total title (10/77).
He beat Safin, Nieminen, Igor, Coria, Gasquet, Nadal, Davydenko and Soderling to win those titles.
Didn’t win anything in 2001, 2006, 2010 and 2011.
And now here's his overall resutls on each surface:
34 outdoor hard titles out of 75 – 45%
20 indoors hard/carpet titles out of 75 – 27%
11 grass titles out of 75 – 15%
10 clay titles out of 75 – 13%
Interesting to see that despite ATP having at least 30% of the total tournaments on clay, Federer has won so far only 10 of them or 13% of his total titles. He went back again and again to Hamburg to win one more clay title as it seemed like the only clay title he was almost guaranteed to win due to its damp and muggy nature.
The 2 Madrid (notorious itself due to bizarre history of the tournament) Masters are the notorious ones as we've seen due to blue clay this year when both Nadal and Nole, the true clay contenders bombing out early. And the previous one, both Nadal and Nole were in a dogfight in the semi and by the time Nadal made the final, he was all out of gas. Thanks to Federer easy draw he remained fresh.
So this is just to show Federer's overall results but in particular his results on clay.