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          471        179 
1992          746        302 
1993         1308        487 
1994         1684        618 
1995         3093       1079 
1996         2980       1053 
1997         1869        645 
1998        22159       9378 
1999        13578       5209 
2000        38735      16015 
2001        39522      15354 
2002        31234      13956 
2003        57924      24101 
2004        46501      17841 
2005        81740      25160 
2006       105390      33819 
2007       192448      59462 
2008       113563      32494 
2009        93913      26462 
2010       120814      33274 
2011       159554      44244 
2012       150788      41780 
2013       223367      63623 
2014       568428     144800 
2015       812035     212888 
2016       664264     172315 
2017       557232     150658 
2018       354573      99588 
2019       869904     212326 
2020       622322     158427 
2021       839750     199626 
2022       626204     179230 
2023       562532     160879 
2024       626060     180297 
2025       187477      53248