Tekstuele beschrijving figuur 39 2019
| - | Aantal opvragingen 2007=100% | Inkomsten in euro, 2007=100% |
| 2007 | 100 | 100 |
| 2008 | 149 | 247 |
| 2009 | 182 | 295 |
| 2010 | 205 | 304 |
| 2011 | 234 | 339 |
| 2012 | 237 | 344 |
| 2013 | 244 | 336 |
| 2014 | 244 | 321 |
| 2015 | 181 | 247 |
| 2016 | 103,41627 | 187,1487 |
| 2017 | 76,27603 | 140,8389 |
| 2018 | 63,466844 | 117,1415 |