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         3114       1086 
1996         3008       1063 
1997         1961        676 
1998        22349       9444 
1999        13625       5229 
2000        38935      16107 
2001        39707      15436 
2002        31161      13961 
2003        58381      24284 
2004        46887      17994 
2005        82418      25359 
2006       106136      34039 
2007       194143      59920 
2008       115993      33134 
2009        95562      26918 
2010       110220      30746 
2011       162632      45080 
2012       153957      42648 
2013       226738      64562 
2014       563427     143849 
2015       783488     205276 
2016       664311     172342 
2017       562634     152178 
2018       360811     101319 
2019       878755     214591 
2020       632107     161052 
2021       852462     202959 
2022       634487     181623 
2023       573614     164013 
2024       640282     184411 
2025        70274      19922