Translating that doesn't seem to take very long though. Looked up an example, Sweden voted to enter EU 13 nov 1994, and legally entered and had thus finished incorporating that into their legislation 1 jan 1995, so 1.5 months at most. Not sure what 5.5 years means, maybe they meant the total amount of working years in manhours saved?
The incorporation of the acquis is part of the negotation process, and had already been completed by the time of the referendum. It had started in 1991, which was unusually fast.
