Year
|
Lower than 10 mg/m³.h
|
10-20 mg/m³.h
|
20-30 mg/m³.h
|
30-50 mg/m³.h
|
Greater than 50 mg/m³.h
|
2004
|
2.0
|
49.3
|
20.1
|
21.3
|
7.2
|
2005
|
24.7
|
18.0
|
18.9
|
28.7
|
9.7
|
2006
|
0.2
|
31.8
|
18.0
|
39.8
|
10.2
|
2007
|
40.3
|
14.6
|
13.6
|
24.5
|
6.9
|
2008
|
21.7
|
31.2
|
21.5
|
25.1
|
0.5
|
2009
|
34.7
|
19.3
|
18.4
|
24.2
|
3.3
|
2010
|
38.9
|
15.1
|
25.1
|
19.0
|
2.0
|
2011
|
32.9
|
16.3
|
25.8
|
21.9
|
3.0
|
2012
|
36.7
|
18.7
|
18.2
|
22.9
|
3.6
|
2013
|
34.4
|
24.2
|
19.3
|
18.3
|
3.7
|
2014
|
33.4
|
31.7
|
25.1
|
9.8
|
0.1
|
2015
|
42.2
|
7.7
|
17.2
|
28.8
|
4.1
|
2016
|
39.1
|
19.2
|
24.1
|
16.6
|
1.0
|
2017
|
43.6
|
16.8
|
18.3
|
18.4
|
3.0
|
2018
|
13.0
|
30.2
|
16.1
|
35.9
|
4.8
|
2019
|
15.6
|
32.2
|
20.9
|
29.0
|
2.4
|