99.999%

The chance that a random game of Freecell (one of the patience/solitaire games that comes with Windows) is solvable is about 99.999%.

It always gives me great pleasure, surely more than it merits, that this number arises for real. It's not made up or hyperbole. An extensive experimental investigation of a million deals had only 14 not solvable. To five significant digits, that's 99.999%.

99.999% of the time that you come across the number 99.999%, somebody has just said it for effect. But 0.001% of the time, it's the result of real study to find the number. And this is that one in a million time. Ok, one in a hundred thousand time.