ᐅ What is considered the year of construction?

Hello everyone,
I have a question and have already searched online but couldn’t find a clear answer.
I started building in May this year (2011), but due to various issues caused by my (now former) developer, only the shell is complete so far, with brick cladding on three sides.
The house is expected to be finished by summer 2012.
What is considered the official construction year? Is it the date when the house is ready to move in?
How was it for you if you built over several years?
Since I want to have a sandstone with the construction year (ANNO 201x) above the entrance, this is quite important to me personally...
Thanks in advance.
Best regards and Happy New Year.
danie87

I believe the foundation laying is the relevant date. A friend is currently building and has the year 2011 marked on the house. He started in September, and at the moment, the screed has just been poured.