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          532        200 
1992          936        367 
1993         1672        611 
1994         2339        844 
1995         4433       1530 
1996         3605       1266 
1997         2337        797 
1998        23359       9846 
1999        14649       5621 
2000        40857      16968 
2001        41941      16368 
2002        33199      14816 
2003        62288      25818 
2004        48949      18786 
2005        87649      26903 
2006       113514      36206 
2007       208610      63825 
2008       129919      36903 
2009       105576      29635 
2010       122585      33990 
2011       185132      51168 
2012       171274      47375 
2013       267824      75931 
2014       666578     169976 
2015       778978     206404 
2016       574672     153850 
2017       548924     151138 
2018       407900     114457 
2019       923145     225446 
2020       717983     184324 
2021      1426995     317287 
2022       693438     198376 
2023       642344     184839 
2024        14778       4621