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          509        192 
1992          936        367 
1993         1669        610 
1994         2329        840 
1995         3826       1325 
1996         3578       1257 
1997         2335        796 
1998        23277       9814 
1999        14550       5580 
2000        40534      16823 
2001        43147      16733 
2002        32614      14580 
2003        61473      25480 
2004        48216      18492 
2005        85967      26418 
2006       111410      35586 
2007       205340      62928 
2008       126380      35949 
2009       102911      28907 
2010       119496      33172 
2011       179336      49591 
2012       166959      46122 
2013       257881      73225 
2014       641886     163656 
2015       745701     197875 
2016       573357     153025 
2017       612404     164122 
2018       404967     113511 
2019       937959     229195 
2020       695799     178478 
2021       903036     216308 
2022       670973     191881 
2023       611360     175990 
2024       170689      48856