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          477        181 
1992          755        305 
1993         1339        498 
1994         1706        626 
1995         3156       1100 
1996         3022       1068 
1997         2021        696 
1998        22666       9572 
1999        13907       5334 
2000        39351      16294 
2001        40074      15592 
2002        31504      14106 
2003        58906      24499 
2004        47064      18061 
2005        82726      25455 
2006       106511      34151 
2007       194923      60129 
2008       116844      33362 
2009        96323      27124 
2010       110968      30944 
2011       163889      45420 
2012       155123      42969 
2013       228377      65018 
2014       556524     142430 
2015       751685     197756 
2016       660439     171381 
2017       566361     153081 
2018       363558     102070 
2019       883091     215714 
2020       636181     162113 
2021       856776     204014 
2022       636913     182317 
2023       574044     164358 
2024       647781     186533 
2025        24209       7065