Table 1: Temporal trends in immunization exemptions to measles-containing vaccine among 17-year-old students in Ontario during the 2002/03 to 2012/13 school years, by exemption classification.

School year	Proportion of students, %
	Medical exemptions	Prior immunity	Religious or conscientious exemptions	Total exemptions
2002/03	0.82	0.47	0.58	1.88
2003/04	0.74	0.47	0.74	1.95
2004/05	1.14	0.47	0.67	2.27
2005/06	0.76	0.39	0.93	2.08
2006/07	0.91	0.39	0.88	2.21
2007/08	0.72	0.31	1.11	2.14
2008/09	0.62	0.22	1.17	2.01
2009/10	0.54	0.16	1.16	1.86
2010/11	0.14	0.13	0.96	1.23
2011/12	0.17	0.12	0.95	1.23
2012/13	0.19	0.12	1.09	1.39
	p < 0.001	p < 0.001	p < 0.001	p < 0.001