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         1308        487 
1994         1686        619 
1995         3108       1084 
1996         2986       1055 
1997         1899        655 
1998        22337       9439 
1999        13611       5224 
2000        38833      16060 
2001        39595      15386 
2002        31014      13894 
2003        58159      24195 
2004        46677      17912 
2005        82061      25252 
2006       105726      33919 
2007       193236      59675 
2008       114935      32850 
2009        94718      26684 
2010       113947      31638 
2011       161139      44677 
2012       155234      43159 
2013       228068      65093 
2014       572250     146052 
2015       801139     209866 
2016       669458     173878 
2017       563368     152521 
2018       362475     101933 
2019       876103     214033 
2020       626806     159627 
2021       846436     201386 
2022       630744     180542 
2023       567161     162198 
2024       632232     182036 
2025       124641      35528