Hi Kez,
As I'm sure you're aware, a design may start in say the 1970's and production could easily continue for 30 or more years , or indeed may be 'resurrected' by another manufacturer at a later stage, there are many reasons that your vase could be from the 70's AND still be on sale in the shops!!! The important thing is that if YOU like it, then carry on loving it!!!
Warmest Wishes,
John