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          471        179 
1992          746        302 
1993         1308        487 
1994         1684        618 
1995         3096       1080 
1996         2983       1054 
1997         1872        646 
1998        22259       9412 
1999        13584       5212 
2000        38763      16028 
2001        39545      15364 
2002        33045      14562 
2003        57991      24128 
2004        46558      17864 
2005        81831      25187 
2006       105479      33846 
2007       192637      59512 
2008       113990      32603 
2009        94158      26529 
2010       120998      33324 
2011       160004      44366 
2012       151224      41897 
2013       223719      63723 
2014       569141     145002 
2015       805204     211031 
2016       664905     172481 
2017       557953     150863 
2018       355293      99792 
2019       871007     212631 
2020       623468     158740 
2021       841802     200135 
2022       627509     179604 
2023       563265     161089 
2024       627502     180697 
2025       169348      48258