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         2018        695 
1998        22659       9569 
1999        13905       5333 
2000        39334      16286 
2001        40060      15585 
2002        31480      14095 
2003        58851      24477 
2004        47047      18054 
2005        82672      25438 
2006       106446      34131 
2007       194744      60082 
2008       116660      33313 
2009        96226      27095 
2010       110858      30916 
2011       163718      45373 
2012       154904      42907 
2013       227989      64911 
2014       557373     142586 
2015       759025     199497 
2016       661002     171503 
2017       565687     152910 
2018       363014     101922 
2019       882121     215467 
2020       635272     161862 
2021       855933     203790 
2022       636386     182171 
2023       573165     164111 
2024       645389     185855 
2025        40709      11771