YEAR Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual 24-hr Avg.
1990 7967 8685 9766 10180 10745 12249 12984 11919 11022 10297 9725 8008 10303
1991 8012 9241 10320 10733 10859 12280 13134 13424 11311 11133 9897 9872 10862
1992 9070 9957 10675 11598 11860 12900 13904 13870 12018 12048 10701 9702 11562
1993 8962 9796 10993 11887 12050 13472 14969 14857 12682 12412 10964 10474 11974
1994 10084 10509 11943 12225 13465 14269 15172 15471 13695 12562 11477 11574 12720
1995 10747 11535 12393 12687 13476 14937 16261 16167 14401 13494 12490 12155 13395
1996 10374 11767 13143 13054 13757 15457 16710 16707 14457 13530 12533 11600 13591
1997 11309 12510 13627 13557 14339 15730 17177 16981 14929 14162 13472 12108 14158
1998 11671 12985 13779 14694 14999 16773 17940 17867 15392 15330
1999 11915 13300 14689 14803 15620 17326 18709 18566 15966 15108 14366 13350 15310
2000 12449 13542 14546 14821 15501 16984 18508 18020 15478 15085 13587 13275 15150
2001 12439 13274 14690 14958 15050 16838 17800 17939 15776 15284 14448 13030 15127
2002 12389 13903 15050 15012 16347 17416 18511 18862 16044 15664 14428 14286 15659
2003 13304 13800 14611 15369 16332 17605 19146 19280 15938 15858 14770 12764 15731
2004 12364 12757 15064 15880 15864 17326 18969 18487 16401 15704 14718 13947 15623
2005 12323 14003 15302 15315 15912 17476 18976 18393 15688 15087 14142 13728 15529
2006 12890 13966 15225 15554 15967 17643 18811 18118 16531 15617 14849 14378 15796
2007 13242 14190 15760 15911 16453 17896 18856 18686 16737 15971 15350 13445 16041
2008 12718 13569 14990 14962 15753 16430 17687 17142 15192 15098  13466
2009 12973 13849 14526 15407 16501 17507 19576 18342 16553 15626 14817 13537 15768
2010 12677 14025 14977 15834 16083 17546 19923 18513 16619 15854 14149 13692 15824
2011 13021 13539 14577 15440 15170 17033 18894 17883 16553 15598