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          743        301 
1993         1308        487 
1994         1684        618 
1995         3081       1075 
1996         2980       1053 
1997         1866        644 
1998        21972       9315 
1999        13562       5203 
2000        38680      15991 
2001        39480      15337 
2002        47676      19430 
2003        57824      24061 
2004        46407      17805 
2005        81580      25112 
2006       105256      33778 
2007       192153      59382 
2008       112898      32316 
2009        93578      26370 
2010       133312      36273 
2011       158793      44039 
2012       150046      41572 
2013       222185      63297 
2014       565934     144177 
2015       798612     210087 
2016       658919     171148 
2017       554516     150124 
2018       353241      99238 
2019       866670     211575 
2020       619665     157746 
2021       835222     198360 
2022       623292     178404 
2023       560689     160371 
2024       621966     179165 
2025       207543      59308