Table 1

Number and rate* (95% confidence interval) of twins in Canada (excluding Ontario) and the United States, 1991-2009
Year Canada (excluding Ontario) United States
Number of live births Twin live births Number of live births Twin live births
Number Rate (95% CI) Number Rate (95% CI)
1991 250847 5027 20.0 (19.5-20.6) 4110907 94779 23.1 (22.9-23.2)
1992 247898 5053 20.4 (19.8-20.9) 4065014 95372 23.5 (23.3-23.6)
1993 240468 4920 20.5 (19.9-21.0) 4000240 96445 24.1 (24.0-24.3)
1994 238069 5013 21.1 (20.5-21.6) 3952767 97064 24.6 (24.4-24.7)
1995 231813 5005 21.6 (21.0-22.2) 3899589 96736 24.8 (24.7-25.0)
1996 226180 5008 22.1 (21.5-22.8) 3891494 100750 25.9 (25.7-26.0)
1997 215588 4975 23.1 (22.4-23.7) 3880894 104137 26.8 (26.7-27.0)
1998 209795 5133 24.5 (23.8-25.1) 3941553 110670 28.1 (27.9-28.2)
1999 206169 5140 24.9 (24.3-25.6) 3959417 114307 28.9 (28.7-29.0)
2000 200476 5117 25.5 (24.8-26.2) 4058814 118916 29.3 (29.1-29.5)
2001 202036 5337 26.4 (25.7-27.1) 4025933 121246 30.1 (29.9-30.3)
2002 200287 5324 26.6 (25.9-27.3) 4021726 125134 31.1 (30.9-31.3)
2003 204279 5753 28.2 (27.4-28.9) 4089950 128665 31.5 (31.3-31.6)
2004 204521 5798 28.3 (27.6-29.1) 4112052 132219 32.2 (32.0-32.3)
2005 208416 5869 28.2 (27.5-28.9) 4138349 133122 32.2 (32.0-32.3)
2006 219202 6665 30.4 (29.7-31.1) 4265555 137085 32.1 (32.0-32.3)
2007 229428 6770 29.5 (28.8-30.2) 4316233 138961 32.2 (32.0-32.4)
2008 237342 6953 29.3 (28.6-30.0) 4247694 138660 32.6 (32.5-32.8)
2009 240823 7564 31.4 (30.7-32.1) 4130665 137217 33.2 (33.0-33.4)

* Rates expressed per 1,000 live births.

Fell and Joseph

Fell and Joseph BMC Pregnancy and Childbirth 2012 12:103   doi:10.1186/1471-2393-12-103

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