World's busiest subway systems

We give you the annual ridership and the year the system opened. You provide the city.
Source: Wikipedia compilation. https://en.wikipedia.org/wiki/List_of_metro_systems and https://en.wikipedia.org/wiki/List_of_urban_rail_systems_in_Japan#Tokyo_(Kant%C5%8D)
In two instances, multiple subway systems in one metro area are combined.
Most data is from 2016, with some from 2014, 2015, and 2017.
Quiz by halpie
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Last updated: March 12, 2018
First submittedMarch 12, 2018
Times taken102
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Annual ridership
Year opened
Answer
3,660,000,000
1971
Beijing
3,401,000,000
1993
Shanghai
3,347,100,000
various
Seoul
3,336,246,726
various
Tokyo
2,800,000,000
1997
Guangzhou
2,378,300,000
1935
Moscow
1,767,100,000
1979
Hong Kong
1,756,800,000
1904
New York City
1,605,000,000
1969
Mexico City
1,518,600,000
1900
Paris
1,378,000,000
1890
London
1,314,000,000
1987
Cairo
1,307,800,000
1974
São Paulo
1,292,200,000
2004
Shenzhen
1,008,000,000
1987
Singapore
Annual ridership
Year opened
Answer
1,007,900,000
2002
Delhi
977,000,000
2005
Nanjing
870,400,000
1933
Osaka
782,000,000
2010
Chengdu
746,000,000
1996
Taipei
740,400,000
1955
Saint Petersburg
717,000,000
1999
Tehran
712,000,000
2004
Wuhan
693,000,000
2005
Chongqing
670,100,000
1975
Santiago
569,700,000
1919
Madrid
534,500,000
1902
Berlin
495,000,000
1983
Caracas
484,600,000
1960
Kiev
472,600,000
1957
Nagoya
+1
Level 48
Sep 22, 2021
Seoul has more riderships than that of Tokyo. I am proud