Lindsay Lohan has been on probation pretty much continuously since August 2007. Before that, she'd already done several stints in rehab, with another one ordered by a judge on Monday. She's been free of any sort of rehab or dealings with the criminal justice system for only 13.6% of her twenties — the six months after she turned 20, and a few months in mid-2007.
CORRECTION: An earlier version of this piece misstated the date of Lohan's 18th birthday. It was July 2, 2004.