| JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | TOTALS | % CHANGE | ||
| 2009 | 13 | 22 | 21 | 16 | 27 | 23 | 23 | 26 | 17 | 22 | 13 | 22 | 245 | 11.4% | INCREASE |
| 2008 | 13 | 21 | 19 | 14 | 21 | 18 | 24 | 22 | 23 | 19 | 10 | 16 | 220 | 18.5% | DECREASE |
| 2007 | 21 | 21 | 30 | 26 | 24 | 25 | 30 | 23 | 14 | 21 | 11 | 24 | 270 | 7.2% | DECREASE |
| 2006 | 23 | 19 | 18 | 24 | 25 | 22 | 30 | 31 | 26 | 19 | 28 | 26 | 291 | 36.6% | INCREASE |
| 2005 | 14 | 14 | 14 | 16 | 16 | 23 | 19 | 28 | 8 | 19 | 21 | 21 | 213 | 9.4% | DECREASE |
| 2004 | 18 | 19 | 22 | 18 | 22 | 21 | 31 | 17 | 14 | 20 | 19 | 14 | 235 | 4.1% | DECREASE |
| 2003 | 15 | 12 | 34 | 24 | 19 | 30 | 23 | 30 | 13 | 13 | 12 | 20 | 245 | 23.7% | DECREASE |
| 2002 | 31 | 19 | 15 | 21 | 24 | 19 | 28 | 44 | 27 | 25 | 29 | 39 | 321 | 21.1% | INCREASE |
| 2001 | 19 | 19 | 22 | 15 | 20 | 23 | 22 | 34 | 21 | 23 | 21 | 26 | 265 | 13.2% | INCREASE |
| 2000 | 21 | 17 | 14 | 10 | 22 | 15 | 32 | 19 | 17 | 23 | 17 | 27 | 234 | 19.4% | INCREASE |
| 1999 | 18 | 12 | 14 | 12 | 23 | 17 | 20 | 16 | 15 | 14 | 15 | 20 | 196 | 25.8% | DECREASE |
| 1998 | 24 | 30 | 23 | 18 | 26 | 22 | 21 | 19 | 26 | 24 | 15 | 16 | 264 | 21.9% | DECREASE |
| 1997 | 31 | 22 | 27 | 27 | 24 | 24 | 18 | 36 | 33 | 42 | 23 | 31 | 338 | 16.1% | DECREASE |
| 1996 | 26 | 25 | 26 | 40 | 37 | 38 | 44 | 40 | 29 | 36 | 30 | 32 | 403 | 5.0% | DECREASE |
| 1995 | 47 | 22 | 31 | 30 | 37 | 43 | 47 | 42 | 38 | 32 | 37 | 18 | 424 | 0.7% | DECREASE |
| 1994 | 27 | 27 | 28 | 46 | 37 | 30 | 48 | 39 | 31 | 40 | 48 | 26 | 427 | 31.8% | INCREASE |
| 1993 | 40 | 34 | 27 | 18 | 33 | 27 | 21 | 30 | 30 | 29 | 21 | 14 | 324 | 8.0% | DECREASE |
| 1992 | 28 | 22 | 20 | 15 | 19 | 28 | 35 | 39 | 38 | 30 | 41 | 37 | 352 | 27.5% | INCREASE |
| 1991 | 18 | 22 | 20 | 19 | 21 | 18 | 27 | 26 | 22 | 26 | 28 | 29 | 276 | 22.1% | INCREASE |
| 1990 | 17 | 27 | 25 | 14 | 18 | 16 | 18 | 17 | 17 | 30 | 15 | 12 | 226 | 5.0% | DECREASE |
| 1989 | 13 | 14 | 15 | 18 | 16 | 14 | 27 | 13 | 24 | 35 | 28 | 21 | 238 | 18.8% | DECREASE |
| 1988 | 41 | 25 | 20 | 26 | 11 | 21 | 28 | 31 | 25 | 22 | 18 | 25 | 293 | 7.3% | DECREASE |
| 1987 | 28 | 23 | 28 | 32 | 23 | 16 | 29 | 44 | 22 | 25 | 26 | 20 | 316 | 10.0% | DECREASE |
| 1986 | 23 | 29 | 29 | 24 | 38 | 30 | 40 | 37 | 21 | 24 | 30 | 26 | 351 | 3.5% | INCREASE |
| 1985 | 24 | 19 | 27 | 26 | 30 | 27 | 32 | 46 | 34 | 24 | 16 | 34 | 339 | 9.7% | INCREASE |
| 1984 | 28 | 30 | 20 | 20 | 32 | 28 | 20 | 28 | 26 | 26 | 22 | 29 | 309 | 1.3% | DECREASE |
| 1983 | 39 | 31 | 27 | 29 | 13 | 25 | 23 | 39 | 21 | 17 | 20 | 29 | 313 | 21.0% | DECREASE |
| 1982 | 22 | 24 | 46 | 19 | 48 | 20 | 38 | 37 | 41 | 36 | 28 | 37 | 396 | 28.6% | INCREASE |
| 1981 | 20 | 16 | 21 | 29 | 21 | 35 | 34 | 29 | 24 | 27 | 20 | 32 | 308 | 5.8% | DECREASE |
| 1980 | 17 | 14 | 22 | 26 | 38 | 27 | 33 | 41 | 31 | 28 | 25 | 25 | 327 | 3.0% | DECREASE |
| 1979 | 19 | 10 | 24 | 25 | 33 | 33 | 39 | 38 | 24 | 29 | 33 | 30 | 337 | 23.4% | INCREASE |
| 1978 | 17 | 24 | 22 | 14 | 19 | 41 | 27 | 28 | 31 | 15 | 14 | 21 | 273 | 12.8% | DECREASE |
| 1977 | 33 | 13 | 20 | 11 | 21 | 29 | 34 | 44 | 31 | 30 | 22 | 25 | 313 | 15.9% | INCREASE |
| 1976 | 21 | 19 | 14 | 16 | 23 | 29 | 31 | 21 | 18 | 26 | 20 | 32 | 270 | 2.7% | INCREASE |
| 1975 | 20 | 28 | 22 | 22 | 10 | 20 | 27 | 18 | 24 | 16 | 25 | 31 | 263 | 23.1% | DECREASE |
| 1974 | 24 | 24 | 24 | 33 | 44 | 42 | 23 | 36 | 26 | 19 | 17 | 30 | 342 | 39.6% | INCREASE |
| 1973 | 17 | 12 | 21 | 14 | 22 | 22 | 21 | 22 | 23 | 25 | 24 | 22 | 245 | 3.5% | DECREASE |