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          532        200 
1992          936        367 
1993         1669        610 
1994         2339        844 
1995         4430       1529 
1996         3605       1266 
1997         2334        796 
1998        23340       9839 
1999        14628       5614 
2000        40797      16942 
2001        41875      16339 
2002        33080      14767 
2003        62158      25766 
2004        48828      18738 
2005        87328      26810 
2006       113194      36110 
2007       208193      63710 
2008       129351      36749 
2009       105012      29483 
2010       122112      33865 
2011       184078      50883 
2012       170645      47204 
2013       266302      75510 
2014       662999     169065 
2015       775399     205446 
2016       575283     153891 
2017       570721     155143 
2018       407450     114319 
2019       926305     226091 
2020       715243     183626 
2021       941962     225919 
2022       690402     197498 
2023       634257     182497 
2024        48494      14058