Graph
Year | Totals | Observation hours |
---|---|---|
1972 | 2728 | 31:00 |
1973 | 2137 | 18:15 |
1974 | 541 | 7:45 |
1975 | 926 | 18:30 |
1976 | 7156 | 66:30 |
1977 | 1344 | 23:45 |
1978 | 13199 | 116:45 |
1979 | 5439 | 71:45 |
1980 | 14726 | 109:00 |
1981 | 14114 | 78:00 |
1982 | 10731 | 39:00 |
1983 | 7687 | 71:00 |
1984 | 1461 | 30:15 |
1985 | 41829 | 98:00 |
1986 | 3156 | 41:30 |
1987 | 2222 | 42:15 |
1988 | 5653 | 55:00 |
1989 | 2234 | 47:15 |
1990 | 5934 | 33:00 |
1991 | 24626 | 18:00 |
1992 | 9928 | 28:30 |
1993 | 7875 | 25:45 |
1994 | 6727 | 40:00 |
1995 | 3563 | 15:15 |
1996 | 670 | 5:00 |
1997 | 267 | 26:30 |
1998 | 151 | 20:00 |
1999 | 4073 | 26:45 |
2000 | 400 | 27:30 |
2001 | 743 | 23:00 |
2002 | 2960 | 26:55 |
2003 | 2657 | 37:45 |
2004 | 4453 | 30:10 |
2005 | 5789 | 34:00 |
2006 | 5210 | 41:33 |
2007 | 6682 | 83:14 |
2008 | 6920 | 56:33 |
2009 | 9406 | 76:07 |
2010 | 4373 | 52:50 |
2011 | 12960 | 80:30 |
2012 | 12473 | 94:05 |
2013 | 29511 | 66:27 |
2014 | 19163 | 41:10 |
2015 | 20941 | 49:05 |
2016 | 37864 | 19:00 |
2017 | 190977 | 123:39 |
2018 | 44643 | 89:34 |
2019 | 19380 | 98:07 |
2020 | 19756 | 108:43 |
2021 | 2782 | 4:45 |