| Year | Fresh groundwater (million m3) | Fresh surface water (million m3) |
|---|---|---|
| 1990 | 311 | 3607 |
| 1995 | 244 | 1761 |
| 2000 | 168 | 750 |
| 2001 | 138 | 736 |
| 2002 | 132 | 734 |
| 2003 | 135 | 729 |
| 2004 | 135 | 717 |
| 2005 | 136 | 716 |
| 2006 | 136 | 718 |
| 2007 | 129 | 756 |
| 2008 | 127 | 734 |
| 2009 | 129 | 736 |
| 2010 | 130 | 721 |
| 2011 | 130 | 718 |
| 2012 | 129 | 721 |
| 2013 | 128 | 711 |
| 2014 | 127 | 710 |
| 2015 | 128 | 712 |
| 2016 | 126 | 717 |
| 2017 | 127 | 713 |