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          465        177 
1992          727        295 
1993         1283        478 
1994         1640        603 
1995         2912       1018 
1996         2907       1028 
1997         1796        622 
1998        21477       9139 
1999        12939       4984 
2000        38099      15740 
2001        40106      15514 
2002        32054      14177 
2003        56629      23597 
2004        45532      17491 
2005        80151      24698 
2006       103227      33189 
2007       188459      58394 
2008       107764      30946 
2009        90180      25456 
2010       142091      38210 
2011       152079      42231 
2012       143384      39773 
2013       215983      61588 
2014       551393     140406 
2015       792389     208419 
2016       648796     168498 
2017       545677     147693 
2018       340851      95812 
2019       851304     207654 
2020       597572     151740 
2021       808119     191397 
2022       609952     174621 
2023       550211     157463 
2024       608849     174874 
2025       475733     135704