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        39685      15427 
2002        31138      13951 
2003        58353      24273 
2004        46870      17987 
2005        82375      25346 
2006       106076      34022 
2007       194062      59898 
2008       115872      33100 
2009        95483      26896 
2010       110083      30710 
2011       162447      45031 
2012       153827      42611 
2013       226463      64489 
2014       568207     144869 
2015       788925     206680 
2016       664249     172324 
2017       562123     152050 
2018       360455     101222 
2019       878047     214413 
2020       631395     160859 
2021       851631     202755 
2022       633942     181468 
2023       572322     163693 
2024       638046     183743 
2025        63519      18162