41.8
43.5
42.4
49
52
20.7
22.2
21.2
18.6
16.6
17
17.4
15.9
15.7
9
17.3
19
14.5
13.7
0
10
20
30
40
50
60
2013
2014
2015
2016
2017
Books house
10 or fewer
11 to 20
21 to 50
More than 50