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         1940        669 
1998        22346       9443 
1999        13620       5227 
2000        38930      16105 
2001        39687      15428 
2002        31146      13954 
2003        58353      24273 
2004        46870      17987 
2005        82381      25348 
2006       106080      34023 
2007       194073      59901 
2008       115872      33100 
2009        95487      26897 
2010       110087      30711 
2011       162455      45033 
2012       153837      42614 
2013       226475      64493 
2014       567162     144667 
2015       787885     206398 
2016       664268     172332 
2017       562153     152059 
2018       360465     101225 
2019       878114     214425 
2020       631450     160875 
2021       851683     202770 
2022       633972     181477 
2023       572372     163707 
2024       638117     183763 
2025        63575      18180