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         1313        489 
1994         1692        621 
1995         3114       1086 
1996         3008       1063 
1997         1961        676 
1998        22349       9444 
1999        13625       5229 
2000        38937      16108 
2001        39709      15437 
2002        31163      13962 
2003        58394      24289 
2004        46887      17994 
2005        82433      25364 
2006       106146      34042 
2007       194203      59936 
2008       116041      33147 
2009        95586      26924 
2010       110294      30766 
2011       162685      45095 
2012       154005      42661 
2013       226871      64600 
2014       562940     143735 
2015       782720     205077 
2016       664399     172362 
2017       563272     152309 
2018       361087     101395 
2019       879261     214709 
2020       632284     161101 
2021       852695     203023 
2022       634710     181688 
2023       573848     164081 
2024       641958     184883 
2025        70967      20100