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         2326        839 
1995         3793       1314 
1996         3578       1257 
1997         2335        796 
1998        23274       9813 
1999        14542       5577 
2000        40514      16813 
2001        43115      16722 
2002        32584      14567 
2003        61392      25449 
2004        48116      18456 
2005        85782      26366 
2006       111201      35523 
2007       204994      62832 
2008       126059      35862 
2009       102596      28823 
2010       119148      33080 
2011       178874      49465 
2012       166022      45939 
2013       257119      72940 
2014       642629     163466 
2015       743797     197382 
2016       573300     152987 
2017       611264     163912 
2018       404262     113320 
2019       942051     230547 
2020       693632     177894 
2021       900820     215779 
2022       668785     191284 
2023       609387     175406 
2024       199829      57482