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         3005       1062 
1997         1934        667 
1998        22346       9443 
1999        13620       5227 
2000        38928      16104 
2001        39680      15425 
2002        31136      13950 
2003        58345      24269 
2004        46869      17987 
2005        82368      25344 
2006       106063      34018 
2007       194036      59891 
2008       115846      33093 
2009        95461      26890 
2010       110068      30706 
2011       162406      45020 
2012       153776      42597 
2013       226404      64472 
2014       569060     145047 
2015       789792     206921 
2016       664305     172337 
2017       562081     152040 
2018       360348     101191 
2019       877858     214391 
2020       631271     160826 
2021       851509     202720 
2022       633861     181445 
2023       573836     163919 
2024       637887     183699 
2025        67600      19177