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          532        200 
1992          936        367 
1993         1669        610 
1994         2339        844 
1995         4430       1529 
1996         3605       1266 
1997         2334        796 
1998        23340       9839 
1999        14636       5617 
2000        40801      16944 
2001        41893      16347 
2002        33098      14774 
2003        62192      25778 
2004        48844      18744 
2005        87353      26817 
2006       113243      36125 
2007       208226      63720 
2008       129386      36759 
2009       105070      29498 
2010       122165      33879 
2011       184170      50907 
2012       170707      47220 
2013       266440      75547 
2014       663669     169230 
2015       775767     205539 
2016       574849     153840 
2017       565934     154364 
2018       407385     114294 
2019       925473     225970 
2020       715477     183676 
2021       928462     223304 
2022       690595     197554 
2023       634929     182693 
2024        48506      14063