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          471        179 
1992          749        303 
1993         1310        488 
1994         1692        621 
1995         3111       1085 
1996         3008       1063 
1997         1952        673 
1998        22346       9443 
1999        13620       5227 
2000        38930      16105 
2001        39689      15429 
2002        31146      13954 
2003        58363      24277 
2004        46880      17991 
2005        82387      25350 
2006       106101      34029 
2007       194084      59904 
2008       115884      33103 
2009        95505      26902 
2010       110126      30722 
2011       162522      45051 
2012       153876      42625 
2013       226526      64504 
2014       566413     144528 
2015       787469     206288 
2016       664317     172346 
2017       562296     152099 
2018       360586     101258 
2019       878424     214506 
2020       631586     160912 
2021       851948     202830 
2022       634088     181510 
2023       572430     163724 
2024       638273     183807 
2025        63593      18183