It says on their website 10-15 days. I can't remember how long mine took but I want to say it was closer to 3 weeks by the time I had them in my hand with my AW score. I took it in August.
ETS sends scores to various schools twice a month. They aggregate all scores that are being sent to that school and send all of them at one time. So If the test is graded 4 weeks after you take it, it could take another 2+ weeks for it to arrive at the school.