Graph
Year | Totals | Observation hours |
---|---|---|
1953 | 0 | 51:15 |
1954 | 0 | 64:45 |
1955 | 0 | 81:45 |
1956 | 0 | 80:00 |
1957 | 0 | 99:45 |
1958 | 0 | 84:00 |
1959 | 0 | 77:00 |
1960 | 0 | 68:45 |
1961 | 0 | 84:30 |
1962 | 0 | 69:30 |
1963 | 0 | 53:30 |
1964 | 3 | 53:15 |
1965 | 0 | 68:30 |
1966 | 0 | 48:45 |
1967 | 0 | 31:00 |
1968 | 0 | 33:15 |
1969 | 0 | 36:15 |
1970 | 0 | 50:30 |
1971 | 0 | 38:15 |
1972 | 0 | 45:45 |
1973 | 0 | 27:15 |
1974 | 0 | 0:00 |
1975 | 0 | 55:15 |
1976 | 2 | 48:00 |
1977 | 16 | 43:15 |
1978 | 7 | 45:00 |
1979 | 18 | 52:00 |
1980 | 21 | 51:45 |
1981 | 19 | 62:00 |
1982 | 248 | 177:30 |
1983 | 0 | 4:15 |
1984 | 56 | 194:00 |
1985 | 111 | 253:45 |
1986 | 73 | 292:00 |
1987 | 314 | 319:40 |
1988 | 105 | 376:10 |
1989 | 36 | 239:42 |
1990 | 30 | 134:45 |
1991 | 9 | 128:00 |
1992 | 61 | 116:30 |
1993 | 48 | 117:45 |
1994 | 2 | 67:00 |
1995 | 5 | 90:30 |
1996 | 16 | 102:10 |
1997 | 0 | 89:00 |
1998 | 0 | 49:45 |
1999 | 31 | 162:00 |
2000 | 8 | 123:30 |
2001 | 145 | 185:15 |
2002 | 89 | 143:15 |
2003 | 20 | 85:30 |
2004 | 47 | 106:30 |
2005 | 8 | 112:30 |
2006 | 0 | 60:00 |
2007 | 1 | 70:30 |
2008 | 30 | 103:51 |
2009 | 46 | 78:30 |
2010 | 291 | 76:30 |
2011 | 99 | 214:15 |
2012 | 293 | 225:50 |
2013 | 64 | 180:30 |
2014 | 182 | 206:35 |
2015 | 35 | 77:15 |
2016 | 63 | 101:05 |
2017 | 27 | 55:40 |
2018 | 19 | 66:31 |
2019 | 47 | 90:45 |
2020 | 149 | 172:21 |
2021 | 56 | 142:00 |
2022 | 188 | 163:17 |