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         3096       1080 
1996         2983       1054 
1997         1872        646 
1998        22310       9429 
1999        13584       5212 
2000        38754      16026 
2001        39547      15365 
2002        42083      17575 
2003        57993      24129 
2004        46574      17870 
2005        81841      25190 
2006       105503      33853 
2007       192673      59522 
2008       114051      32618 
2009        94185      26536 
2010       119524      32965 
2011       160168      44415 
2012       154221      42891 
2013       227009      64815 
2014       572284     146052 
2015       802481     210272 
2016       665109     172534 
2017       558063     150893 
2018       355391      99819 
2019       871173     212665 
2020       623752     158782 
2021       842123     200228 
2022       627775     179681 
2023       563409     161130 
2024       628198     180880 
2025       169742      48357