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         1902        656 
1998        22340       9440 
1999        13611       5224 
2000        38844      16065 
2001        39618      15396 
2002        31019      13896 
2003        58190      24205 
2004        46702      17921 
2005        82090      25261 
2006       105779      33934 
2007       193373      59712 
2008       115058      32884 
2009        94829      26714 
2010       114049      31664 
2011       161340      44730 
2012       152621      42280 
2013       225159      64127 
2014       569181     145041 
2015       798793     209189 
2016       664091     172220 
2017       560044     151458 
2018       357986     100535 
2019       874816     213613 
2020       628045     159909 
2021       847091     201567 
2022       631263     180694 
2023       568958     162614 
2024       633515     182393 
2025       125044      35651