Surveys with 24 hours' urinary salt data included
| Dates of 24 hours' urine collection | N included in analyses | |
| National Diet and Nutrition Survey 2000/1 | July 2000 to June 2001 | 1029 |
| England 2006 sodium survey | October 2005 to July 2006 | 445 |
| UK 2008 sodium survey | January to May 2008 | 571 |
| England 2011 sodium survey | July to December 2011 | 499 |
| England 2014 sodium survey | May to September 2014 | 622 |
| National Diet and Nutrition Survey Rolling Programme (sensitivity analyses only) | ||
| 2008 | January to December 2008 | 75 |
| 2009 | January to December 2009 | 96 |
| 2010 | January to December 2010 | 101 |
| 2011 | January to December 2011 | 154 |
| 2012 | January to December 2012 | 153 |
| 2013 | January to June 2013 | 88 |