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          512        193 
1992          936        367 
1993         1669        610 
1994         2329        840 
1995         4361       1505 
1996         3593       1262 
1997         2334        796 
1998        23312       9827 
1999        14583       5594 
2000        40643      16874 
2001        41651      16244 
2002        32776      14647 
2003        61711      25577 
2004        48484      18601 
2005        86563      26593 
2006       112068      35779 
2007       206652      63291 
2008       127564      36266 
2009       103836      29159 
2010       120488      33433 
2011       181406      50156 
2012       168444      46600 
2013       261986      74301 
2014       648836     165469 
2015       756797     200793 
2016       579729     154640 
2017       610990     163169 
2018       407675     114241 
2019       932512     227374 
2020       702226     180355 
2021       911232     218719 
2022       680292     194578 
2023       617979     177864 
2024       138329      39636