"It is three years since" vs. "It has been three years since"

[herbivorie]

This is an example from a grammar book, so there is not context.

It is three years since my sister got married.

I always thought that it should be "It has been * years" before "since".
Is there a difference in this between AmE and BrE?

 

[MikeNewYork]

In AmE, both are correct.

 

[Rover_KE]

They're both correct in BrE, too.