Category
2018
2015
2013
2010
2007
Don't know
0
1
0
1
1
I have never heard of it (%)
70
73
73
78
80
I've heard of it but I do not know what it is (%)
19
16
16
13
12
I've heard of it and I know what it is (%)
11
10
11
8
6