Table 2 Study population

11,912,797

11,205,770

11,269,412

11,978,011

12,244,671

0

56.45

52.25

52.75

53.64

55.16

1

0.62

0.60

0.52

0.80

1.41

2

14.73

15.07

13.83

13.40

14.35

3

16.67

17.75

17.51

17.59

17.69

4

11.52

14.33

15.40

14.56

11.39

Male

45.40

45.33

45.65

45.95

45.96

Female

54.60

54.66

54.34

54.04

54.04

<18

13.38

12.97

12.60

12.08

11.88

18 to 59

39.43

37.84

37.44

36.92

36.62

60 to 79

35.61

36.45

36.69

36.93

36.86

>79

19.84

21.65

22.41

23.52

24.13

Mean (days)

7.31

7.51

7.29

7.35

7.26

Stdev (days)

3.15

3.16

3.03

3.05

3.03