Graph
Year | Totals | Observation hours |
---|---|---|
1900 | 2 | 5:30 |
1980 | 58 | 2:00 |
1981 | 12252 | 143:25 |
1982 | 10570 | 100:04 |
1983 | 2587 | 76:05 |
1984 | 37330 | 157:55 |
1985 | 7656 | 193:05 |
1986 | 29300 | 180:40 |
1987 | 17357 | 99:15 |
1988 | 17933 | 216:00 |
1989 | 21975 | 269:46 |
1990 | 140004 | 262:45 |
1991 | 174090 | 405:47 |
1992 | 82793 | 645:00 |
1993 | 57920 | 397:58 |
1994 | 70521 | 286:00 |
1995 | 76637 | 224:45 |
1996 | 55501 | 328:00 |
1997 | 62484 | 356:45 |
1998 | 95548 | 339:30 |
1999 | 49674 | 267:15 |
2000 | 37015 | 261:30 |
2001 | 58332 | 525:35 |
2002 | 71579 | 526:15 |
2003 | 935357 | 567:15 |
2004 | 150798 | 455:05 |
2005 | 267043 | 601:15 |
2006 | 22747 | 389:55 |
2007 | 73419 | 432:55 |
2008 | 489540 | 525:55 |
2009 | 151239 | 399:05 |
2010 | 123781 | 249:40 |
2011 | 125767 | 319:15 |
2012 | 39158 | 231:35 |
2013 | 44025 | 270:55 |
2014 | 66364 | 291:35 |
2015 | 61207 | 177:30 |
2016 | 18222 | 230:15 |
2017 | 35370 | 250:05 |
2018 | 64356 | 318:16 |
2019 | 585063 | 584:19 |
2020 | 174733 | 587:17 |
2021 | 79255 | 646:27 |
2022 | 113336 | 640:14 |
2023 | 164053 | 346:27 |