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        40532      16822 
2001        43137      16732 
2002        32614      14580 
2003        61462      25477 
2004        48207      18489 
2005        85963      26417 
2006       111410      35586 
2007       205306      62919 
2008       126376      35948 
2009       102884      28900 
2010       119475      33166 
2011       179313      49585 
2012       166959      46122 
2013       257838      73213 
2014       641839     163643 
2015       745691     197872 
2016       573334     153019 
2017       612647     164195 
2018       405023     113528 
2019       939211     229551 
2020       695799     178478 
2021       904073     216505 
2022       670585     191770 
2023       611329     175980 
2024       176005      50396