| Year | Type | TOTAL | |||
| b | ntHi | a,c,d,e,f | Not typed | ||
| 1990 | 864 | 40 | 9 | 402 | 1315 |
| 1991 | 903 | 64 | 8 | 350 | 1325 |
| 1992 | 871 | 62 | 13 | 267 | 1213 |
| 1993 | 293 | 106 | 18 | 192 | 609 |
| 1994 | 85 | 105 | 9 | 151 | 350 |
| 1995 | 73 | 175 | 28 | 111 | 387 |
| 1996 | 53 | 150 | 34 | 102 | 339 |
| 1997 | 60 | 181 | 24 | 112 | 377 |
| 1998 | 36 | 221 | 25 | 106 | 388 |
| 1999 | 67 | 185 | 17 | 110 | 379 |
| 2000 | 100 | 219 | 29 | 128 | 476 |
| 2001 | 149 | 237 | 37 | 131 | 554 |
| 2002 | 271 | 240 | 35 | 125 | 671 |
| 2003 | 266 | 262 | 45 | 111 | 684 |
| 2004 | 167 | 232 | 39 | 91 | 529 |
| 2005 | 124 | 273 | 52 | 114 | 563 |
| 2006 | 116 | 303 | 50 | 130 | 599 |
| 2007 | 92 | 272 | 40 | 226 | 630 |
| 2008 | 73 | 314 | 61 | 224 | 672 |
| 2009 | 37 | 360 | 57 | 203 | 657 |
| 2010 | 30 | 305 | 66 | 145 | 546 |
* Provisional data
Source: Routine laboratory data combined with reference laboratory data
Last reviewed: 2 September 2011