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          492        186 
1992          767        309 
1993         1356        504 
1994         1749        641 
1995         3303       1149 
1996         3315       1166 
1997         2291        783 
1998        23113       9750 
1999        14432       5532 
2000        40009      16590 
2001        40852      15915 
2002        32078      14336 
2003        59925      24886 
2004        47345      18166 
2005        83195      25596 
2006       107339      34391 
2007       197136      60719 
2008       118637      33850 
2009        97663      27490 
2010       112416      31313 
2011       166533      46130 
2012       157147      43513 
2013       232775      66244 
2014       576479     147039 
2015       754972     197501 
2016       671588     173881 
2017       572822     154728 
2018       369817     103776 
2019       893718     218395 
2020       645525     164589 
2021       865005     206156 
2022       641228     183587 
2023       586073     167622 
2024       515367     148916