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         1308        487 
1994         1686        619 
1995         3108       1084 
1996         2991       1057 
1997         1917        661 
1998        22337       9439 
1999        13614       5225 
2000        38854      16070 
2001        39638      15405 
2002        31039      13907 
2003        58206      24212 
2004        46717      17928 
2005        82127      25273 
2006       105853      33956 
2007       193457      59733 
2008       115189      32918 
2009        94924      26740 
2010       114140      31687 
2011       161460      44763 
2012       152757      42316 
2013       225375      64188 
2014       568944     145001 
2015       797264     208792 
2016       664348     172291 
2017       560358     151546 
2018       358317     100625 
2019       875269     213720 
2020       630103     160396 
2021       847652     201697 
2022       631675     180815 
2023       569319     162692 
2024       634354     182636 
2025       125420      35786