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          492        186 
1992          770        310 
1993         1356        504 
1994         2258        815 
1995         3362       1169 
1996         3573       1255 
1997         2326        793 
1998        23237       9798 
1999        14508       5563 
2000        40402      16763 
2001        42961      16659 
2002        32422      14492 
2003        61026      25307 
2004        47840      18351 
2005        84881      26101 
2006       110307      35255 
2007       203050      62308 
2008       124275      35382 
2009       100880      28360 
2010       117477      32644 
2011       175773      48613 
2012       163522      45220 
2013       252474      71432 
2014       601118     153962 
2015       727025     192790 
2016       709703     183578 
2017       599114     161703 
2018       394208     110473 
2019       928055     227854 
2020       680802     174317 
2021       891335     213276 
2022       661951     189315 
2023       599315     172568 
2024       262590      76099