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          749        303 
1993         1308        487 
1994         1686        619 
1995         3099       1081 
1996         2986       1055 
1997         1890        652 
1998        22327       9435 
1999        13595       5217 
2000        38783      16039 
2001        39574      15376 
2002        30978      13878 
2003        58063      24155 
2004        46611      17884 
2005        81959      25222 
2006       105599      33882 
2007       192958      59598 
2008       114478      32732 
2009        94430      26604 
2010       116092      32138 
2011       160642      44541 
2012       154694      43014 
2013       227626      64972 
2014       571880     145934 
2015       801502     210002 
2016       670961     174315 
2017       562538     152292 
2018       361371     101627 
2019       874472     213631 
2020       625364     159228 
2021       844152     200763 
2022       629342     180134 
2023       565270     161668 
2024       631719     181871 
2025       153770      43577