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        22316       9431 
1999        13584       5212 
2000        38754      16026 
2001        39547      15365 
2002        42083      17575 
2003        58002      24130 
2004        46574      17870 
2005        81845      25191 
2006       105503      33853 
2007       192673      59522 
2008       114054      32619 
2009        94196      26539 
2010       119532      32967 
2011       160104      44392 
2012       151301      41918 
2013       223793      63743 
2014       569008     144961 
2015       802579     210233 
2016       665458     172620 
2017       558100     150903 
2018       355442      99830 
2019       871206     212673 
2020       623755     158781 
2021       842152     200236 
2022       627805     179690 
2023       563428     161135 
2024       628218     180886 
2025       169835      48387