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          444        170 
1992          721        293 
1993         1280        477 
1994         1628        599 
1995         2885       1009 
1996         2883       1020 
1997         1784        618 
1998        21445       9125 
1999        12849       4952 
2000        37850      15629 
2001        39051      15138 
2002        34791      15078 
2003        56564      23529 
2004        45025      17309 
2005        79496      24496 
2006       102362      32931 
2007       186511      57868 
2008       104385      30032 
2009        87924      24854 
2010       140389      37764 
2011       148236      41185 
2012       139017      38585 
2013       212779      60694 
2014       539950     137387 
2015       796046     209555 
2016       633357     163717 
2017       545318     147727 
2018       333674      93862 
2019       845674     206649 
2020       583797     147887 
2021       794123     187618 
2022       602333     172444 
2023       543357     155495 
2024       599318     172212 
2025       572196     163774