55%
Tier 1
35%
Tier 2
10%
Tier 3
1%
2
2%
3
3%
4
4%
5
5%
6
6%
7
7%
8
8%
9
9%
10
10%
11
9%
12
8%
13
7%
14
6%
15
5%
16
4%
17
3%
18
2%
19
1%
20
2
1%
3
2%
4
3%
5
4%
6
5%
7
6%
8
7%
9
8%
10
9%
11
10%
12
9%
13
8%
14
7%
15
6%
16
5%
17
4%
18
3%
19
2%
20
1%