Year Observations     Objects
1950            2          1 
1951            6          3 
1953            4          2 
1954            2          1 
1955            4          2 
1956            2          1 
1960            6          3 
1974            2          1 
1975            2          1 
1976            8          4 
1977            2          1 
1978            8          3 
1981            4          2 
1982           12          6 
1983            8          4 
1984            2          1 
1985            8          4 
1986            4          2 
1987            2          1 
1988           38         18 
1990           32         14 
1991          477        181 
1992          755        305 
1993         1339        498 
1994         1706        626 
1995         3156       1100 
1996         3022       1068 
1997         2018        695 
1998        22656       9568 
1999        13903       5332 
2000        39328      16283 
2001        40046      15578 
2002        31475      14093 
2003        58820      24465 
2004        47032      18048 
2005        82654      25432 
2006       106437      34128 
2007       194648      60057 
2008       116604      33298 
2009        96163      27077 
2010       110803      30902 
2011       163617      45346 
2012       154767      42868 
2013       227861      64874 
2014       557898     142686 
2015       761748     200181 
2016       660940     171487 
2017       565416     152847 
2018       362857     101878 
2019       881815     215388 
2020       634968     161776 
2021       855477     203685 
2022       636219     182122 
2023       572846     164017 
2024       644268     185535 
2025        44591      12956