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         4433       1530 
1996         3605       1266 
1997         2337        797 
1998        23359       9846 
1999        14651       5622 
2000        40872      16975 
2001        41967      16378 
2002        33224      14827 
2003        62316      25829 
2004        48957      18789 
2005        87693      26914 
2006       113561      36220 
2007       208676      63843 
2008       129995      36924 
2009       105637      29652 
2010       122634      34003 
2011       185261      51203 
2012       171344      47392 
2013       267951      75965 
2014       666856     170044 
2015       779212     206469 
2016       574598     153849 
2017       547629     150878 
2018       407954     114477 
2019       922694     225350 
2020       718407     184403 
2021      1070030     251464 
2022       693801     198477 
2023       642829     184979 
2024         9454       2913