By the numbers: First round
40: The number of PGA Professionals in the field at the 74th Senior PGA Championship presented by KitchenAid.
29: The number of players who recorded a round under par in Thursday's first round.
66: Or, 5 under par, the best score recorded on Thursday by co-leaders Jay Haas and Duffy Waldorf.
4.5548: The scoring average on the 477-yard, par-4 10th hole Thursday, which played as the most difficult in Round 1.
4.5705: The scoring average on the 522-yard, par-5 fourth hole Thursday, which played as the easiest in Round 1.
70: The age of Tom Wargo, a four-time winner on the Champions Tour, who is the oldest competitor in the field. He also lives just 90 minutes away, in Centralia, Ill. In 1993, Wargo defeated Bruce Crampton in a two-hole playoff to become the last PGA Club Professional to capture this major championship.
5: The number of past PGA Champions in the field this week at Bellerive (Lanny Wadkins, Mark Brooks, Jeff Sluman, Bob Tway and Hal Sutton).
72: Or, 1 over par, the opening round score for defending champ Roger Chapman.
2: The number of PGA Club Professionals in the top 10 after the first round -- Sonny Skinner (4-under 67, T3) and Mark Mielke (2-under 69, T8).
2: The number of players to complete Round 1 without a bogey -- Jay Haas (5-under 66, T1) and Mark Wiebe (1-under 70, T18).