1980s
6.1
5.5
6.1
0.0
6.6
6.2
7.0
6.0
5.6
6.8
7.2
0.0
6.1
0.0
7.1
7.2
6.8
6.9
7.1
6.9
0.0
6.7
5.9
5.2
6.4
7.8
5.9
5.9
4.8
6.2
5.2
8.0
6.2
7.1
0.0
7.1
7.9
6.6
6.2
5.8
5.8
6.5
7.4
6.0
7.1
6.3
7.1
5.2
5.9
7.4
7.1
7.0
6.0
6.4
5.6
6.9
0.0
6.4
7.2
6.9
0.0
6.0
6.0
7.4
6.5
7.2
0.0
7.2
7.0
6.9
7.6
0.0
0.0
6.9
6.4
7.2
6.4
5.8
7.4
6.2
7.2
7.2
0.0
