in which year did he have his most wins in grand slam matches?
2012
col : tournament | 2007 | 2008 | 2009 | 2010 | 2011 | 2012 | 2013 | 2014 | w–l row 1 : australian open | 1r | 1r | a | 2r | 1r | 3r | 2r | 1r | 4–7 row 2 : french open | q1 | q1 | a | 2r | q1 | 1r | 1r |  | 1–3 row 3 : wimbledon | q1 | a | 1r | 2r | 1r | 3r | 1r |  | 3–5 row 4 : us open | q3 | q2 | q3 | 1r | 1r | 1r | 1r |  | 0–4 row 5 : win–loss | 0–1 | 0–1 | 0–1 | 3–4 | 0–3 | 4–4 | 1–4 | 0–1 | 8–19 row 6 : titles–finals | 0–0 | 0–0 | 0–0 | 0–0 | 0–0 | 0–1 | 0–0 |  | 0–1 row 7 : year-end ranking | 139 | 325 | 82 | 89 | 112 | 51 | 81 |  |
in which year did he have his most wins in grand slam matches?
Tournament 2007 2008 2009 2010 2011 2012 2013 2014 W–L
Australian Open 1R 1R A 2R 1R 3R 2R 1R 4–7
French Open Q1 Q1 A 2R Q1 1R 1R 1–3
Wimbledon Q1 A 1R 2R 1R 3R 1R 3–5
US Open Q3 Q2 Q3 1R 1R 1R 1R 0–4
Win–Loss 0–1 0–1 0–1 3–4 0–3 4–4 1–4 0–1 8–19
Titles–Finals 0–0 0–0 0–0 0–0 0–0 0–1 0–0 0–1
Year-End Ranking 139 325 82 89 112 51 81
2012