Year Observations     Objects
1950            2          1 
1951            6          3 
1953           14          8 
1954           12          5 
1955           12          6 
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          856        306 
1992          656        270 
1993         1176        442 
1994         1487        555 
1995         2362        834 
1996         2628        933 
1997         2509        857 
1998        23933       8551 
1999        12849       4900 
2000        36366      14935 
2001        41440      16274 
2002        35017      14985 
2003        57016      23354 
2004        44854      17085 
2005       303216     136631 
2006       330616     147633 
2007       191817      59426 
2008       107909      30785 
2009        88439      24743 
2010       136113      36255 
2011       143048      38925 
2012       170571      37003 
2013       224835      56588 
2014       472022     117136 
2015       710992     185957 
2016       599814     155000 
2017       504772     137239 
2018       301415      85243 
2019       804083     196966 
2020       527563     133694 
2021       710542     166325 
2022       551956     158315 
2023       509967     146105 
2024       550152     158137 
2025       524381     148776 
2026       369484      87965