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         1925        664 
1998        22343       9442 
1999        13620       5227 
2000        38916      16099 
2001        39671      15421 
2002        31110      13939 
2003        58327      24262 
2004        46849      17979 
2005        82315      25328 
2006       106034      34009 
2007       193945      59866 
2008       115740      33065 
2009        95337      26855 
2010       109963      30678 
2011       162263      44981 
2012       153571      42540 
2013       226226      64423 
2014       569041     145070 
2015       790275     207033 
2016       664805     172462 
2017       561713     151936 
2018       359991     101092 
2019       877369     214264 
2020       630662     160659 
2021       850770     202512 
2022       633496     181339 
2023       572615     163602 
2024       636491     183303 
2025        91700      25880