In order to simplify your paperwork USDA recommends the following:
Ask your veterinarian to give your pet a 1-year rabies vaccination (after scanning the microchip) at least 21 days before your travel to the EU but less than one year before your travel date (for example, 3-6 months before travel date). That way, no matter the rabies vaccination history, you only have to keep up with one vaccination certificate instead of several! Doing it this way also makes it easier for the USDA endorsement office to review, which means you get your endorsed certificate back faster.
Courtesy of USDA