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          503        190 
1992          936        367 
1993         1669        610 
1994         2329        840 
1995         3799       1316 
1996         3578       1257 
1997         2335        796 
1998        23277       9814 
1999        14545       5578 
2000        40526      16819 
2001        43123      16726 
2002        32594      14571 
2003        61418      25460 
2004        48163      18473 
2005        85888      26395 
2006       111300      35553 
2007       205121      62865 
2008       126224      35907 
2009       102722      28857 
2010       119279      33114 
2011       179086      49524 
2012       166270      46009 
2013       260005      73264 
2014       641119     163449 
2015       744809     197638 
2016       573323     152987 
2017       611436     163962 
2018       404511     113388 
2019       941798     230363 
2020       694593     178162 
2021       901791     216006 
2022       669926     191566 
2023       610301     175663 
2024       200909      57815