Beijing

Shanghai

Chengdu

Guangzhou

Shenyang

Wuhan

Total

N

20s

90

37

68

74

101

79

449

30s

27

86

56

49

22

30

270

40s

62

46

51

56

49

38

302

50s

40

39

46

33

53

52

263

60s

5

19

5

4

2

24

59

Age (mean ± SD)

20s

24.8 ± 2.3

25.6 ± 2.1

25.9 ± 1.8

26.1 ± 2.0

26.0 ± 1.7

24.9 ± 1.9

25.6 ± 2.0

30s

35.5 ± 2.7

34.2 ± 2.7

34.9 ± 2.9

35.1 ± 3.2

35.8 ± 3.4

33.3 ± 2.8

34.6 ± 2.8

40s

44.1 ± 3.1

44.7 ± 2.7

44.1 ± 2.5

44.5 ± 3.0

45.0 ± 3.0

45.8 ± 3.0

44.5 ± 2.9

50s

54.3 ± 2.7

55.0 ± 3.1

53.7 ± 2.8

53.7 ± 3.1

53.8 ± 2.3

54.4 ± 2.9

54.2 ± 2.8

60s

62.2 ± 2.3

62.6 ± 1.6

61.8 ± 2.2

62.3 ± 2.1

64.0 ± 1.4

62.1 ± 2.0

62.2 ± 1.8