Table 3.

Incidence rate ratios for men and women by calendar period and age group. (The 25–29 age group is the reference age group).

Age group	1997–2001		2002–2007		2008–2012
	IRR	95% CI	IRR	95% CI	IRR	95% CI
Men
15–19	0.45	0.19–1.07	0.24	0.14–0.41	0.16	0.10–0.26
20–24	0.86	0.44–1.69	0.78	0.54–1.11	0.75	0.55–1.03
25–29	1		1		1
30–34	0.91	0.42–1.98	0.69	0.45–1.05	1.04	0.67–1.62
35–39	0.67	0.25–1.76	0.71	0.46–1.11	0.89	0.60–1.32
40–44	0.86	0.38–1.93	0.76	0.43–1.33	0.62	0.38–1.01
45–49	1.25	0.11–14.60	0.53	0.25–1.11	0.64	0.26–1.56
Women
15–19	1.21	0.58–2.50	0.69	0.49–0.97	0.61	0.46–0.81
20–24	1.17	0.58–2.34	0.99	0.74–1.31	1.10	0.90–1.35
25–29	1		1		1
30–34	0.89	0.35–2.29	0.72	0.50–1.05	0.74	0.57–0.96
35–39	0.68	0.23–2.02	0.61	0.39–0.97	0.52	0.34–0.79
40–44	0.86	0.28–2.64	0.40	0.25–0.64	0.45	0.31–0.66
45–49	0.72	0.15–3.41	0.29	0.16–0.55	0.33	0.21–0.53

CI, confidence interval; IRR, incidence rate ratios.