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         1678        613 
1994         2339        844 
1995         4439       1532 
1996         3605       1266 
1997         2337        797 
1998        23365       9848 
1999        14654       5623 
2000        40880      16979 
2001        41982      16385 
2002        33265      14845 
2003        62370      25850 
2004        49000      18806 
2005        87779      26941 
2006       113689      36257 
2007       208911      63906 
2008       130247      36993 
2009       105854      29711 
2010       122880      34066 
2011       185768      51340 
2012       171733      47498 
2013       268808      76199 
2014       668068     170369 
2015       780948     206939 
2016       574267     153866 
2017       542587     150164 
2018       411061     115344 
2019       925885     226212 
2020       722501     185517 
2021      1056406     249484 
2022       695634     198995 
2023       646081     185887 
2024         3944       1176