found this timeline in a story about the 40th anniversary 370Z coming out in 2010…
Z car milestones
Oct. 22, 1969: The Datsun 240Z (Nissan Fairlady Z in Japan) goes on sale in the United States.
1974: The inline six-cylinder engine grows to 2.6 liters and the name changes to 260Z. A 2+2 model is added.
1975: The engine grows to 2.8 liters and the name changes to 280Z.
1979: Second-generation 280ZX is introduced.
1981: 280ZX Turbo joins the lineup.
1984: Nissan launches third-generation 300ZX with 3.0-liter V6.
1990: Fourth-generation 300ZX arrives, with 222 hp. 300ZX Turbo follows with 300 hp.
1996: Nissan drops Z car from U.S. market.
1999: Nissan shows a 240Z concept at the Detroit auto show. But it is rejected for production.
2001: Nissan shows a reworked Z Concept at the Detroit auto show. Nissan CEO Carlos Ghosn says the car will go into production.
2003: Fifth-generation 350Z goes on sale with 3.5-liter V6.
2008: Sixth-generation 370Z unveiled at Los Angeles auto show.
2009: A convertible version of the 370Z goes on sale.