In het postcodegebied 1851 is het aantal inwoners sinds 1998 als volgt opgebouwd :
| Jaar | Inwoners | Groei |
| 1998 | 11,765 | |
| 1999 | 12,055 | 2.46% |
| 2000 | 12,180 | 1.04% |
| 2001 | 12,200 | 0.16% |
| 2002 | 12,195 | -0.04% |
| 2003 | 12,240 | 0.37% |
| 2004 | 12,210 | -0.25% |
| 2005 | 12,235 | 0.20% |
| 2006 | 12,205 | -0.25% |
| 2007 | 12,205 | 0.00% |
| 2008 | 12,340 | 1.11% |
| 2009 | 12,465 | 1.01% |
| 2010 | 12,510 | 0.36% |
| 2011 | 12,545 | 0.28% |
| .2012 | 12,535 | -0.08% |
| 2013 | 12,495 | -0.32% |
| 2014 | 12,425 | -0.56% |
| 2015 | 12,370 | -0.44% |
| 2016 | 12,435 | 0.53% |
| 2017 | 12,455 | 0.16% |
| 2018 | 12,450 | -0.04% |
| 2019 | 12,560 | 0.88% |
| 2020 | 12,780 | 1.75% |