| Marketing Year |
June | July | Aug. | Sep. | Oct. | Nov. | Dec. | Jan. | Feb. | Mar. | Apr. | May |
| Percent | ||||||||||||
| 2006-07 | 3 | 11 | 9 | 7 | 9 | 12 | 14 | 12 | 10 | 7 | 4 | 2 |
| 2005-06 | 3 | 12 | 9 | 8 | 11 | 11 | 13 | 10 | 8 | 6 | 4 | 5 |
| 2004-05 | 3 | 12 | 9 | 8 | 11 | 11 | 13 | 10 | 8 | 6 | 4 | 5 |
| 2003-04 | 3 | 7 | 8 | 7 | 9 | 18 | 14 | 11 | 9 | 7 | 4 | 3 |
| 2002-03 | 3 | 8 | 11 | 10 | 12 | 18 | 12 | 9 | 6 | 5 | 3 | 3 |
| 2001-02 | 6 | 10 | 10 | 12 | 13 | 11 | 9 | 10 | 8 | 5 | 4 | 2 |
| 2000-01 | 3 | 11 | 10 | 7 | 9 | 14 | 12 | 13 | 9 | 7 | 3 | 2 |
| 1999-00 | 5 | 10 | 10 | 12 | 14 | 14 | 11 | 8 | 7 | 4 | 3 | 2 |
| 1998-99 | 5 | 13 | 10 | 15 | 15 | 11 | 10 | 8 | 6 | 3 | 3 | 1 |
| 1997-98 | 8 | 11 | 11 | 9 | 10 | 11 | 10 | 9 | 7 | 7 | 4 | 3 |
| 1996-97 | 5 | 13 | 10 | 15 | 15 | 11 | 10 | 8 | 6 | 3 | 3 | 1 |
| 1995-96 | 5 | 5 | 9 | 9 | 8 | 17 | 12 | 10 | 8 | 9 | 6 | 2 |
| 1994-95 | 5 | 5 | 9 | 9 | 8 | 17 | 12 | 10 | 8 | 9 | 6 | 2 |
| 1993-94 | 3 | 7 | 7 | 8 | 12 | 14 | 17 | 10 | 10 | 7 | 3 | 2 |
| 1992-93 | 3 | 7 | 7 | 8 | 12 | 14 | 17 | 10 | 10 | 7 | 3 | 2 |
| 1991-92 | 3 | 11 | 13 | 7 | 8 | 7 | 10 | 12 | 9 | 8 | 6 | 6 |
| 1990-91 | 10 | 8 | 10 | 10 | 11 | 9 | 7 | 10 | 7 | 9 | 4 | 5 |
| 1989-90 | 6 | 12 | 11 | 8 | 9 | 12 | 12 | 9 | 8 | 7 | 4 | 2 |
| 1988-89 | 8 | 13 | 11 | 8 | 10 | 12 | 12 | 8 | 6 | 6 | 4 | 2 |
| 1987-88 | 2 | 7 | 9 | 5 | 9 | 11 | 13 | 9 | 10 | 11 | 7 | 7 |
| 1986-87 | 3 | 6 | 10 | 5 | 10 | 12 | 12 | 10 | 9 | 10 | 5 | 8 |
| 1985-86 | 5 | 11 | 6 | 8 | 9 | 10 | 13 | 10 | 9 | 9 | 7 | 3 |
| 1984-85 | 3 | 9 | 6 | 9 | 10 | 11 | 13 | 11 | 9 | 10 | 6 | 3 |
| 1983-84 | 2 | 15 | 13 | 3 | 11 | 14 | 12 | 10 | 10 | 4 | 3 | 3 |
| 1982-83 | 2 | 14 | 7 | 3 | 5 | 9 | 16 | 8 | 15 | 10 | 8 | 3 |
| 1981-82 | 5 | 4 | 5 | 4 | 7 | 15 | 15 | 13 | 11 | 7 | 10 | 4 |
| 1980-81 | 5 | 10 | 7 | 6 | 9 | 15 | 13 | 8 | 9 | 8 | 5 | 5 |
| 1979-80 | 2 | 3 | 5 | 6 | 8 | 8 | 17 | 12 | 10 | 9 | 11 | 8 |
| 1978-79 | 2 | 4 | 6 | 6 | 7 | 11 | 14 | 18 | 16 | 8 | 5 | 3 |
| 1977-78 | 3 | 4 | 7 | 6 | 8 | 12 | 16 | 13 | 11 | 10 | 7 | 3 |
| 1976-77 | 2 | 3 | 5 | 6 | 7 | 12 | 19 | 14 | 12 | 10 | 7 | 3 |
| 1975-76 | 2 | 3 | 5 | 6 | 7 | 12 | 19 | 14 | 12 | 10 | 7 | 3 |