With the promise of study breaks and, in some cases, the threat of withholding dining hall access, 4,545 undergraduates were counted in the 2010 census on Tuesday. Ezra Stiles College had the highest participation rate (98.9 percent), and Davenport had the lowest (89.8 percent). “We’re going to get that last 5 percent tomorrow,” census coordinator David Broockman ’11 said.