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          489        185 
1992          764        308 
1993         1356        504 
1994         1746        640 
1995         3282       1142 
1996         3072       1085 
1997         2282        780 
1998        23066       9732 
1999        14401       5521 
2000        39945      16560 
2001        40673      15844 
2002        31866      14257 
2003        59571      24753 
2004        47192      18108 
2005        82840      25485 
2006       106693      34203 
2007       195364      60248 
2008       117194      33457 
2009        96629      27204 
2010       111226      31012 
2011       164488      45580 
2012       155580      43089 
2013       229130      65228 
2014       553186     141803 
2015       722789     190434 
2016       660721     171414 
2017       567877     153454 
2018       364600     102347 
2019       886548     216478 
2020       637718     162535 
2021       858315     204397 
2022       637716     182538 
2023       577596     165412 
2024       652766     187948 
2025        23768       7007