Halladay's has to be the leader in the clubhouse - 86 strikes in 105 pitches - 81.90% (8/25/12 Phi vs Wash, W 4-2, 7 IP, 7 H, 2 R, 2 ER, 1 BB, 6 K) Scherzer is at 80.67%
And Bartolo Colon had 80 strikes in 99 pitches once for 80.81% (5/29/05 LAA vs KC, W 7-6, 7.2 IP, 12 H, 4 R, 4 ER, 0 BB, 6 K)
Wells has done it twice - 81/100 (4/19/01 for CWS vs Det- W 4-2, 9 IP, 8 H, 1 R, 1 ER, 0 BB, 6 K) and 84/104 (8/30/97 for NYY vs Mon - L 7-2, 8 IP, 9 H, 6 R, 4 ER, 1 BB, 8 K)
Found the Schilling game, 9/20/02 - LOL, he got pounded. 114 pitches, 94 strikes - 7.2 IP, 14 H, 9 R, 8 ER, 1 BB, 3 K