Two years have the same calendar if they're both common years or both leap years, and start on the same day. 2007 starts on Monday (common year). Checking forward: 2008 (+2 days, leap), 2009 (+1), 2010 (+1), 2011 (+1), 2012 (+1), 2013 (+2 from leap 2012, total +6 = Monday, common year). 2014 starts on Tuesday, so 2007's calendar repeats in 2014 (both common years starting on Monday after accounting for leap years).