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         3826       1325 
1996         3578       1257 
1997         2335        796 
1998        23277       9814 
1999        14550       5580 
2000        40532      16822 
2001        43147      16733 
2002        32614      14580 
2003        61465      25478 
2004        48207      18489 
2005        85963      26417 
2006       111410      35586 
2007       205312      62921 
2008       126376      35948 
2009       102904      28905 
2010       119482      33168 
2011       179317      49586 
2012       166959      46122 
2013       257851      73217 
2014       641862     163650 
2015       745694     197873 
2016       573330     153018 
2017       612561     164166 
2018       405015     113526 
2019       938547     229373 
2020       695737     178461 
2021       902960     216286 
2022       670624     191782 
2023       611342     175984 
2024       172999      49519