Buckle up, Tiger stats fans. Essential stuff you need to know going into the weekend.

1. There’s always a defining moment at sports events. It normally comes on Sunday afternoon at golf tournaments. The Majors don’t start until the back nine on Sunday, say the players. Well, the 91st USPGA was all but done on the back nine on Friday. This week’s defining moment came when Tiger Woods was still leading at the halfway stage. He’s eight from eight when leading after 36 holes at the Majors. When leading PGA tournaments after the second round he has won 32 out of 38 times. After three rounds it’s 47 out of 50. Worldwide in all tournaments he has won 50 out of 56. “He’s plays nice golf,” as Padraig said here. Yes he does, doesn’t he?

2. Tiger is marching to Major No.15. If Tiger does win the PGA, then follows up next year with the Masters (Augusta) and US Open (Pebble Beach), he has a chance to tie Jack Nicklaus at the Open at the home of golf, St Andrews, the course where Jack retired from in 2005. How’s that for an historical coincidence. Tiger could then erase Jack from the record books by winning the 2010 PGA Championship at Whistling Straits to complete a calendar Grand Slam. OK, that’s a lot of ifs and buts, but it is Tiger we are talking about here.

3. Tiger versus Jack: who’s the greatest? This is Tiger’s 50th Major. He’s won 29 percent of his 49 starts. Jack won 24 percent of his first 49 Majors.

4. Tiger won his 70th Tour event at last week’s WGC event at Bridgestone, aged 33. Jack was 40 when he got to 70 victories He was 46 when he won his 73rd and last. Tiger could quite possibly topple that stat this year. Then he’ll be chasing Sam Snead’s 82. After that, there’s just immortality.

5. This is Tiger’s 12th year on tour. He has won 30 percent of the tournaments he has played in. That’s 70 out of 234. In Jack’s first 12 years, he won 21 percent (52 out of 253). Tiger has five victories this season already (and counting).

Right, I’ve now got headache after all that number-crunching. Time for an ice cream.