Graph
Year | Totals | Observation hours |
---|---|---|
1971 | 0 | 1:15 |
1972 | 0 | 0:30 |
1974 | 1 | 6:30 |
1977 | 0 | 2:30 |
1982 | 1 | 1:50 |
1983 | 6 | 13:30 |
1984 | 31 | 12:30 |
1985 | 46 | 20:15 |
1986 | 4 | 2:00 |
1987 | 0 | 3:30 |
1988 | 2 | 3:15 |
1989 | 17 | 9:30 |
1990 | 0 | 0:00 |
1991 | 13 | 4:30 |
1992 | 7 | 3:00 |
1993 | 10 | 6:46 |
1994 | 0 | 1:00 |
1995 | 29 | 9:45 |
1996 | 23 | 5:15 |
1997 | 2 | 6:15 |
1998 | 6 | 6:30 |
1999 | 0 | 4:15 |
2000 | 25 | 8:45 |
2001 | 72 | 24:00 |
2002 | 10 | 11:30 |
2003 | 3 | 6:14 |
2004 | 172 | 52:15 |
2005 | 489 | 370:45 |
2006 | 530 | 560:00 |
2007 | 419 | 568:00 |
2008 | 738 | 623:30 |
2009 | 200 | 346:10 |
2010 | 554 | 257:51 |
2011 | 876 | 379:30 |
2012 | 578 | 474:30 |
2013 | 247 | 449:30 |
2014 | 281 | 366:57 |
2015 | 148 | 241:57 |
2016 | 216 | 386:02 |
2017 | 130 | 309:56 |
2018 | 113 | 319:16 |
2019 | 86 | 243:15 |
2020 | 784 | 304:06 |
2021 | 381 | 186:53 |