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          746        302 
1993         1308        487 
1994         1684        618 
1995         3099       1081 
1996         2986       1055 
1997         1890        652 
1998        22325       9434 
1999        13590       5215 
2000        38760      16029 
2001        39560      15370 
2002        32098      14249 
2003        58045      24147 
2004        46591      17876 
2005        81908      25208 
2006       105550      33867 
2007       192799      59556 
2008       114254      32672 
2009        94285      26565 
2010       117584      32494 
2011       160368      44464 
2012       151611      42005 
2013       224221      63865 
2014       568611     144863 
2015       800342     209612 
2016       666164     172802 
2017       558472     151007 
2018       356017      99996 
2019       872066     212902 
2020       624555     159004 
2021       843031     200477 
2022       628710     179950 
2023       564592     161474 
2024       630993     181678 
2025       169608      48298