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          532        200 
1992          936        367 
1993         1678        613 
1994         2339        844 
1995         4436       1531 
1996         3605       1266 
1997         2337        797 
1998        23359       9846 
1999        14654       5623 
2000        40878      16978 
2001        41980      16384 
2002        33257      14841 
2003        62368      25849 
2004        48992      18803 
2005        87773      26939 
2006       113682      36256 
2007       208854      63891 
2008       130192      36979 
2009       105813      29700 
2010       122860      34061 
2011       185708      51324 
2012       171676      47482 
2013       268735      76179 
2014       667915     170327 
2015       780801     206898 
2016       574752     153974 
2017       546266     150910 
2018       411207     115377 
2019       926208     226264 
2020       722341     185470 
2021       931050     224072 
2022       695486     198952 
2023       645314     185674 
2024         5031       1493