I checked my subscription to Touringplans.com, and the crowd levels are as follows:
12th: 10 out of 10 (Reopening of Dumbo)
13th: 10
14th: 10
15th: 8
16th: 10
19th: 10
20th: 10
21st: 9
22nd: 9
23rd: 10
So obviously not the best time of year to go. I was there on a 9.8 day last year at the opening of Star Tours during Star Wars Weekends, and it was like sardines in a can. You can have fun even in those conditions if you use the fastpass system correctly though. Have fun!