YEAR Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 24-hr Avg.
1998 4163 4721 5213 5651 6123 6221 5644 6358 6289 6244 5452
1999 
2000     6538  7856 7579 6563 5952 5323 4887
2001 5647 5655 6562         4389
2002 
2003  8165 8214 8939
2004      7701 8629 8893
2005 
2006 
2007 
2008