Table 1 Background characteristics of the seven provincial-level administrative divisions in region 1 and region 2 during 2010–2019

Cities (hospitals)^a

10 (24)

1 (10)

1 (11)

1 (19)

12 (16)

13 (29)

17 (25)

Population size (million)^b

74.25

15.47

21.71

24.15

55.39

79.76

55.39

Latitude (°N)

38.1

39.2

39.9

31.3

30

32.9

31.8

Longitude (°E)

115.8

117.2

116.4

121.5

120.4

118.6

117.5

Mean winter temperature (°C)

1.2

3.5

1.8

10.5

11.3

8.2

8.6

Mean winter relative humidity (%)

54.6

54.4

49.9

69.5

74.1

71.8

70.4

Urbanization rate^c

49.3%

82.3%

86.5%

87.6%

67.0%

67.7%

50.5%