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         1669        610 
1994         2339        844 
1995         4430       1529 
1996         3605       1266 
1997         2337        797 
1998        23342       9840 
1999        14642       5619 
2000        40803      16945 
2001        41899      16350 
2002        33109      14779 
2003        62209      25786 
2004        48869      18754 
2005        87387      26828 
2006       113273      36134 
2007       208278      63734 
2008       129435      36772 
2009       105104      29507 
2010       122211      33891 
2011       184238      50925 
2012       170753      47233 
2013       266547      75576 
2014       663978     169311 
2015       776077     205626 
2016       574570     153824 
2017       564313     154092 
2018       407364     114293 
2019       925517     225980 
2020       715612     183714 
2021       966556     226937 
2022       690814     197614 
2023       635258     182787 
2024        47199      13662