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          468        178 
1992          735        298 
1993         1283        478 
1994         1655        608 
1995         2945       1029 
1996         2941       1040 
1997         1810        627 
1998        21552       9170 
1999        13056       5025 
2000        38217      15793 
2001        39132      15196 
2002        30568      13696 
2003        57125      23788 
2004        45826      17595 
2005        80526      24808 
2006       103837      33368 
2007       189896      58777 
2008       109763      31480 
2009        91415      25787 
2010       143179      38495 
2011       154206      42806 
2012       145647      40389 
2013       217486      62003 
2014       557792     142124 
2015       797273     209702 
2016       654112     169930 
2017       549188     148655 
2018       345327      97052 
2019       857566     209255 
2020       606676     154256 
2021       816434     193659 
2022       613218     175548 
2023       553215     158307 
2024       607550     174926 
2025       371045     106721