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         3823       1324 
1996         3578       1257 
1997         2335        796 
1998        23277       9814 
1999        14550       5580 
2000        40526      16819 
2001        43135      16731 
2002        32610      14578 
2003        61455      25474 
2004        48204      18488 
2005        85936      26410 
2006       111396      35581 
2007       205241      62901 
2008       126326      35934 
2009       102854      28892 
2010       119429      33154 
2011       179263      49572 
2012       166853      46100 
2013       257727      73180 
2014       641705     163607 
2015       745500     197821 
2016       573187     152984 
2017       612390     164150 
2018       404914     113501 
2019       940303     229830 
2020       695528     178401 
2021       903568     216384 
2022       669798     191562 
2023       611110     175926 
2024       180858      51855