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          477        181 
1992          755        305 
1993         1339        498 
1994         1706        626 
1995         3156       1100 
1996         3022       1068 
1997         2021        696 
1998        22663       9571 
1999        13905       5333 
2000        39334      16286 
2001        40062      15586 
2002        31484      14097 
2003        58860      24481 
2004        47057      18058 
2005        82711      25450 
2006       106466      34137 
2007       194795      60095 
2008       116690      33321 
2009        96245      27101 
2010       110925      30933 
2011       163797      45395 
2012       154981      42929 
2013       228109      64945 
2014       556953     142527 
2015       758883     199502 
2016       661161     171536 
2017       565929     152969 
2018       363211     101975 
2019       882515     215568 
2020       635685     161980 
2021       856267     203870 
2022       636631     182240 
2023       573471     164197 
2024       646515     186173 
2025        39075      11238