The Tokaido Shinkansen in Japan has served nearly 5.5 billion passengers since it started in 1964

"Since it's opening in 1964, the Tokaido Shinkansen has served approximately 5.1 billion passengers. It was the countrys first shinkansen...it can be said to have supported the economic growth of Japan" 

Source:

 Tsubame

By Umezawa Akira, 

Nipponica, No 6, 2012, page 10