Woods has not won one of golf's elite championships since his remarkable playoff victory at the 2008 US Open, often playing his way into contention over the first two rounds in recent years only for his game to fade over the weekend.
"It kind of seems that way," he told reporters on Tuesday. "It's been probably the longest spell that I've had since I last won a Major championship.
"I came out here (on the US Tour) very early and got my first one back in '97."
Woods turned professional in late 1996 and romped to a record 12-stroke victory the following April as he became the youngest ever winner at the Masters, aged 21.
He piled up a further 13 Major titles over the next decade at an astonishing rate before his barren run began, hardly helped by the breakdown of his marriage in early 2010, assorted injury problems and the fourth swing change of his career.
"I've had my opportunities there on the back nine on probably half of those Sundays for the last five years where I've had a chance, and just haven't won it," he said.
"But the key is to keep giving myself chances, and eventually I'll start getting them."
Woods comes into Oak Hill for the year's final Major on a high, having romped to victory by seven shots in the elite WGC-Bridgestone Invitational on Sunday.
Every aspect of his game appeared to be in top order last week as he clinched the 79th US Tour victory of his career, and a record eighth title in the World Golf Championships (WGC) event.
"Obviously I feel pretty good about winning by seven and coming here," smiled Woods, who claimed the most recent of his four PGA Championship titles in 2007.
"Overall, I feel very pleased with where my game is at. I've played well in the last two tournaments I've played in, especially coming off a little bit of an injury (wrist) at the
(U.S.) Open. I'm very pleased about that."
Woods tied for sixth in last month's Open at Muirfield, where he was ultimately undone by poor putting as his title bid unravelled with a three-over-par 74 in the final round.
The in-form Woods, who has been installed as the PGA Championship favourite at 7-2 by British bookmakers William Hill, said he would describe his year as "great" even if he failed to triumph this week.
"This year, for me, has been a great year so far, winning five times," he explained. "And you look at the quality of tournaments I've won, a Players (title) and two World Golf Championships in there, that's pretty good."
Pressed on whether it would still be a great year for him if he ended his 2013 campaign without a single Major title, Woods replied: "Yeah, I think so.
"We certainly have, what, four more big events after this," he said, referring to the US Tour's lucrative end-of-season play-off events. "A lot of things can happen, but I'm focused on this week and trying to win this one."