GPRD study population by year and the subset with HES data available
| Year | GPRD | GPRD with HES |
|---|---|---|
| 1990 | 1 088 206 | |
| 1991 | 1 318 334 | |
| 1992 | 1 508 239 | |
| 1993 | 1 630 354 | |
| 1994 | 1 750 630 | |
| 1995 | 1 862 669 | |
| 1996 | 2 224 963 | |
| 1997 | 2 551 363 | 1 149 379 |
| 1998 | 2 978 905 | 1 345 591 |
| 1999 | 3 561 968 | 1 592 080 |
| 2000 | 3 951 452 | 1 760 716 |
| 2001 | 4 256 165 | 1 892 812 |
| 2002 | 4 508 721 | 1 949 061 |
| 2003 | 4 629 896 | 1 968 050 |
| 2004 | 4 778 854 | 2 018 928 |
| 2005 | 4 858 541 | 2 059 654 |
| 2006 | 4 961 506 | 2 116 992 |
| 2007 | 5 017 396 | 2 184 142 |
| 2008 | 4 989 868 | 2 223 688 |
| 2009 | 4 955 179 | 2 240 931 |
| 2010 | 4 972 336 | 1 981 005 |
| 2011 | 4 665 090 |
GPRD, General Practice Research Database; HES, Hospital Episode Statistics.