Graph
Year | Totals | Observation hours |
---|---|---|
1971 | 3 | 1:15 |
1972 | 0 | 0:30 |
1974 | 137 | 6:30 |
1977 | 28 | 2:30 |
1982 | 0 | 1:50 |
1983 | 2 | 13:30 |
1984 | 37 | 12:30 |
1985 | 11 | 20:15 |
1986 | 0 | 2:00 |
1987 | 13 | 3:30 |
1988 | 250 | 3:15 |
1989 | 36 | 9:30 |
1990 | 0 | 0:00 |
1991 | 0 | 4:30 |
1992 | 0 | 3:00 |
1993 | 68 | 6:46 |
1994 | 0 | 1:00 |
1995 | 23 | 9:45 |
1996 | 25 | 5:15 |
1997 | 25 | 6:15 |
1998 | 0 | 6:30 |
1999 | 303 | 4:15 |
2000 | 6 | 8:45 |
2001 | 3003 | 24:00 |
2002 | 143 | 11:30 |
2003 | 73 | 6:14 |
2004 | 117 | 52:15 |
2005 | 8469 | 370:45 |
2006 | 26737 | 560:00 |
2007 | 28620 | 568:00 |
2008 | 30343 | 623:30 |
2009 | 14134 | 346:10 |
2010 | 6070 | 257:51 |
2011 | 13395 | 379:30 |
2012 | 13829 | 474:30 |
2013 | 13139 | 449:30 |
2014 | 8304 | 366:57 |
2015 | 7310 | 241:57 |
2016 | 11667 | 386:02 |
2017 | 9125 | 309:56 |
2018 | 5464 | 319:16 |
2019 | 7839 | 243:15 |
2020 | 4788 | 304:06 |
2021 | 2839 | 186:53 |