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         1887        651 
1998        22325       9434 
1999        13588       5214 
2000        38760      16029 
2001        39560      15370 
2002        32084      14244 
2003        58040      24145 
2004        46587      17875 
2005        81880      25201 
2006       105544      33865 
2007       192733      59538 
2008       114186      32654 
2009        94255      26556 
2010       117601      32505 
2011       160319      44450 
2012       151528      41982 
2013       224127      63837 
2014       568771     144902 
2015       800649     209721 
2016       665974     172754 
2017       558475     151004 
2018       355886      99957 
2019       871801     212848 
2020       624383     158957 
2021       842759     200400 
2022       628456     179875 
2023       564425     161424 
2024       630775     181608 
2025       171479      48838