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          732        297 
1993         1283        478 
1994         1643        604 
1995         2933       1025 
1996         2936       1038 
1997         1801        624 
1998        21531       9161 
1999        13000       5005 
2000        38174      15775 
2001        39063      15169 
2002        30896      13804 
2003        56993      23737 
2004        45744      17568 
2005        80430      24779 
2006       103659      33316 
2007       189551      58683 
2008       109197      31327 
2009        91094      25699 
2010       142823      38401 
2011       153565      42629 
2012       145046      40223 
2013       216999      61874 
2014       555889     141604 
2015       795725     209291 
2016       652534     169498 
2017       548145     148367 
2018       343945      96677 
2019       855980     208850 
2020       603860     153471 
2021       813796     192950 
2022       612449     175331 
2023       552382     158071 
2024       606739     174667 
2025       417462     120073