Year Observations     Objects
1950            2          1 
1951            6          3 
1953           14          8 
1954           12          5 
1955           12          6 
1956            8          4 
1960            6          3 
1974            2          1 
1975            2          1 
1976            8          4 
1977            2          1 
1978           12          5 
1981           18          5 
1982           13          7 
1983            8          4 
1984            2          1 
1985            8          4 
1986            4          2 
1987            2          1 
1988           38         18 
1990          216         77 
1991          856        306 
1992          664        273 
1993         1198        450 
1994         1528        569 
1995         2496        880 
1996         2737        970 
1997         2626        896 
1998        24116       8607 
1999        12949       4936 
2000        36640      15052 
2001        41694      16381 
2002        35247      15084 
2003        57533      23546 
2004        45334      17256 
2005       304714     137193 
2006       331918     148129 
2007       193105      59767 
2008       109657      31250 
2009        90268      25230 
2010       138339      36828 
2011       145779      39649 
2012       173607      37814 
2013       229270      57788 
2014       477136     118482 
2015       719266     188234 
2016       607504     157130 
2017       515073     140123 
2018       306473      86655 
2019       811025     198782 
2020       533848     135458 
2021       722995     169608 
2022       561824     161093 
2023       514836     147475 
2024       555453     159644 
2025       530130     150362 
2026       299142      67320