Year Observations     Objects
1950            2          1 
1951            6          3 
1953           14          8 
1954           12          5 
1955           14          7 
1956            8          4 
1960            6          3 
1974            2          1 
1975            2          1 
1976            8          4 
1977            2          1 
1978           12          5 
1981           18          5 
1982           13          7 
1983            8          4 
1984            2          1 
1985            8          4 
1986            4          2 
1987            2          1 
1988           38         18 
1990          216         77 
1991          861        308 
1992          675        277 
1993         1222        458 
1994         1581        587 
1995         2705        950 
1996         2799        991 
1997         2768        943 
1998        24388       8708 
1999        13179       5023 
2000        37200      15307 
2001        42222      16603 
2002        35767      15307 
2003        58435      23907 
2004        45980      17504 
2005       308534     138803 
2006       335206     149479 
2007       194973      60258 
2008       111821      31826 
2009        92497      25827 
2010       140769      37467 
2011       149647      40686 
2012       177183      38783 
2013       233619      58973 
2014       530859     130387 
2015       756063     196977 
2016       626661     161727 
2017       525263     142794 
2018       313127      88505 
2019       821335     201303 
2020       543075     137714 
2021       736901     172700 
2022       570802     163616 
2023       521874     149472 
2024       565948     162631 
2025       547568     155139 
2026       248810      53117