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         2116        767 
1995         3351       1165 
1996         3564       1252 
1997         2320        791 
1998        23180       9776 
1999        14481       5552 
2000        40184      16666 
2001        41072      16006 
2002        32180      14392 
2003        60495      25104 
2004        47613      18262 
2005        84011      25844 
2006       108814      34821 
2007       200050      61503 
2008       121571      34644 
2009        99145      27893 
2010       114908      31971 
2011       170401      47172 
2012       159846      44239 
2013       241022      68477 
2014       583389     149839 
2015       706407     187392 
2016       678634     176198 
2017       578248     156296 
2018       378933     106281 
2019       906187     221845 
2020       654970     167270 
2021       872852     208162 
2022       655916     187596 
2023       600370     171461 
2024       339049      98363