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         3820       1323 
1996         3578       1257 
1997         2335        796 
1998        23277       9814 
1999        14550       5580 
2000        40526      16819 
2001        43135      16731 
2002        32604      14576 
2003        61455      25474 
2004        48204      18488 
2005        85933      26409 
2006       111396      35581 
2007       205235      62898 
2008       126316      35932 
2009       102850      28891 
2010       119417      33151 
2011       179236      49565 
2012       166499      46070 
2013       257659      73166 
2014       641641     163588 
2015       745405     197795 
2016       573256     152989 
2017       612320     164134 
2018       404912     113500 
2019       940543     229896 
2020       695423     178372 
2021       902623     216202 
2022       669782     191558 
2023       611042     175906 
2024       192033      55146