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          503        190 
1992          936        367 
1993         1669        610 
1994         2329        840 
1995         3826       1325 
1996         3578       1257 
1997         2335        796 
1998        23277       9814 
1999        14550       5580 
2000        40526      16819 
2001        43137      16732 
2002        32612      14579 
2003        61458      25475 
2004        48204      18488 
2005        85937      26410 
2006       111392      35580 
2007       205274      62910 
2008       126352      35941 
2009       102861      28894 
2010       119438      33156 
2011       179273      49574 
2012       166879      46107 
2013       257743      73184 
2014       641756     163620 
2015       745556     197835 
2016       573174     152978 
2017       612347     164140 
2018       404916     113499 
2019       939340     229594 
2020       695600     178421 
2021       903658     216410 
2022       669962     191605 
2023       611140     175934 
2024       176089      50421