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          477        181 
1992          755        305 
1993         1339        498 
1994         1706        626 
1995         3156       1100 
1996         3022       1068 
1997         2018        695 
1998        22654       9567 
1999        13886       5326 
2000        39318      16279 
2001        40039      15575 
2002        31413      14072 
2003        58780      24448 
2004        47014      18041 
2005        82617      25421 
2006       106402      34117 
2007       194573      60037 
2008       116507      33272 
2009        96032      27042 
2010       110717      30879 
2011       163426      45294 
2012       154633      42831 
2013       227685      64827 
2014       558116     142718 
2015       765219     201012 
2016       662484     171870 
2017       565090     152764 
2018       362596     101806 
2019       881416     215271 
2020       634503     161660 
2021       855038     203567 
2022       636004     182061 
2023       572505     163917 
2024       643501     185319 
2025        53972      14646