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          477        181 
1992          755        305 
1993         1339        498 
1994         1706        626 
1995         3156       1100 
1996         3022       1068 
1997         2021        696 
1998        22663       9571 
1999        13907       5334 
2000        39349      16293 
2001        40072      15591 
2002        31502      14105 
2003        58893      24494 
2004        47062      18060 
2005        82724      25454 
2006       106496      34146 
2007       194908      60125 
2008       116802      33351 
2009        96309      27120 
2010       110960      30942 
2011       163868      45414 
2012       155099      42962 
2013       228335      65005 
2014       557022     142547 
2015       755755     198744 
2016       660559     171407 
2017       566343     153076 
2018       363505     102056 
2019       882925     215673 
2020       636046     162076 
2021       856675     203985 
2022       636882     182309 
2023       573946     164331 
2024       647429     186434 
2025        29213       8375