(%)
< >| Time of the last usage | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020a |
|---|
| Have used it ever | 45.9 | 54.0 | 61.7 | 62.9 | 66.9 | 71.4 | 73.9 | 75.6 | 77.9 | 78.8 | 81.1 | 83.0 | 83.9 | 85.8 | 87.5 |
| Within the last 3 months | 42.6 | 51.1 | 57.7 | 58.5 | 61.3 | 67.3 | 70.3 | 72.4 | 75.7 | 72.8 | 79.3 | 76.8 | 76.1 | 80.4 | 84.8 |
| Between 3 months and a year ago | 2.1 | 1.7 | 2.4 | 2.5 | 3.1 | 2.3 | 1.8 | 1.7 | 1.3 | 3.1 | 1.4 | 2.6 | 3.4 | 2.3 | 1.3 |
| More than 1 year ago | 1.2 | 1.2 | 1.6 | 1.9 | 2.5 | 1.8 | 1.8 | 1.5 | 1.0 | 2.9 | 0.5 | 3.6 | 4.4 | 3.0 | 1.4 |