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Comparisons of prevalences of collisions before and after 2009.
| 2002–2008 | 2010–2016 | Difference | Х2(1) | p-Value | |
|---|---|---|---|---|---|
| Smokers | 9.39% (n = 2103.70) |
7.01% (n = 1608.34) |
2.38% 95% CI (0.62%,4.15%) |
6.77 | 0.009 |
| Nonsmokers | 7.08% (n = 8251.79) |
6.02% (n = 8496.77) |
1.06% 95% CI (0.31%,1.81%) |
7.85 | 0.006 |
| Difference | 2.31% 95%CI (0.95%,3.68%) |
0.99% 95% CI (−0.36%,2.33%) |
|||
| Х2(1) | 12.85 | 2.27 | |||
| p-Value | <0.001 | 0.132 |
