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          749        303 
1993         1310        488 
1994         1692        621 
1995         3111       1085 
1996         3005       1062 
1997         1934        667 
1998        22346       9443 
1999        13620       5227 
2000        38928      16104 
2001        39683      15426 
2002        31138      13951 
2003        58349      24271 
2004        46870      17987 
2005        82368      25344 
2006       106073      34021 
2007       194054      59896 
2008       115857      33096 
2009        95483      26896 
2010       110071      30707 
2011       162419      45024 
2012       153801      42604 
2013       226438      64482 
2014       568916     145009 
2015       789531     206858 
2016       664282     172333 
2017       562096     152044 
2018       360383     101201 
2019       877991     214405 
2020       631336     160844 
2021       851559     202734 
2022       633903     181457 
2023       573902     163938 
2024       637965     183720 
2025        65804      18729