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         3117       1087 
1996         3008       1063 
1997         1961        676 
1998        22349       9444 
1999        13625       5229 
2000        38941      16110 
2001        39711      15438 
2002        31171      13966 
2003        58416      24298 
2004        46895      17997 
2005        82447      25369 
2006       106157      34045 
2007       194240      59946 
2008       116089      33160 
2009        95620      26933 
2010       110354      30781 
2011       162773      45119 
2012       154057      42676 
2013       226976      64630 
2014       562542     143633 
2015       782316     204975 
2016       664479     172384 
2017       563380     152341 
2018       361257     101440 
2019       879444     214759 
2020       632531     161170 
2021       852936     203093 
2022       634851     181729 
2023       574133     164162 
2024       642474     185026 
2025        71956      20367