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         3108       1084 
1996         2989       1056 
1997         1905        657 
1998        22337       9439 
1999        13614       5225 
2000        38846      16066 
2001        39623      15399 
2002        31018      13897 
2003        58192      24206 
2004        46712      17925 
2005        82102      25266 
2006       105803      33941 
2007       193394      59717 
2008       115114      32899 
2009        94845      26718 
2010       114070      31670 
2011       161377      44740 
2012       152670      42293 
2013       225235      64149 
2014       569136     145028 
2015       798762     209168 
2016       664191     172247 
2017       560146     151488 
2018       358107     100568 
2019       874944     213650 
2020       629675     160274 
2021       847233     201607 
2022       631374     180725 
2023       568733     162552 
2024       634121     182572 
2025       125360      35744