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         1672        611 
1994         2339        844 
1995         4430       1529 
1996         3605       1266 
1997         2337        797 
1998        23345       9841 
1999        14646       5620 
2000        40832      16958 
2001        41928      16362 
2002        33167      14802 
2003        62273      25812 
2004        48889      18762 
2005        87560      26877 
2006       113401      36172 
2007       208521      63801 
2008       129768      36863 
2009       105372      29580 
2010       122452      33954 
2011       184794      51075 
2012       171099      47328 
2013       267386      75811 
2014       665920     169807 
2015       778401     206249 
2016       574916     153920 
2017       553730     152058 
2018       407837     114437 
2019       924520     225806 
2020       717374     184162 
2021      1066522     250643 
2022       692680     198160 
2023       639056     183883 
2024        16911       5263