Graph
Year | Totals | Observation hours |
---|---|---|
1900 | 172 | 5:30 |
1980 | 0 | 2:00 |
1981 | 0 | 143:25 |
1982 | 0 | 100:04 |
1983 | 1982 | 76:05 |
1984 | 2258 | 157:55 |
1985 | 4364 | 193:05 |
1986 | 2773 | 180:40 |
1987 | 3169 | 99:15 |
1988 | 5641 | 216:00 |
1989 | 5124 | 269:46 |
1990 | 3949 | 262:45 |
1991 | 5435 | 405:47 |
1992 | 15512 | 645:00 |
1993 | 6826 | 397:58 |
1994 | 16724 | 286:00 |
1995 | 9532 | 224:45 |
1996 | 6495 | 328:00 |
1997 | 7106 | 356:45 |
1998 | 17920 | 339:30 |
1999 | 9488 | 267:15 |
2000 | 9098 | 261:30 |
2001 | 18012 | 525:35 |
2002 | 3019 | 526:15 |
2003 | 3657 | 567:15 |
2004 | 4198 | 455:05 |
2005 | 5015 | 601:15 |
2006 | 3745 | 389:55 |
2007 | 3809 | 432:55 |
2008 | 10931 | 525:55 |
2009 | 5287 | 399:05 |
2010 | 1674 | 249:40 |
2011 | 10092 | 319:15 |
2012 | 8520 | 231:35 |
2013 | 1956 | 270:55 |
2014 | 4875 | 291:35 |
2015 | 1345 | 177:30 |
2016 | 6250 | 230:15 |
2017 | 5639 | 250:05 |
2018 | 6431 | 318:16 |
2019 | 7103 | 584:19 |
2020 | 6587 | 587:17 |
2021 | 6501 | 646:27 |
2022 | 5725 | 479:35 |