A perfect score for a year means that EVERY response scored a 9 or 10 when asked "On a scale of zero to ten, how likely are you to recommend us". There are years when no dealer scores this, we have only had one dealer achieve it 2 years in a row. See here for how difficult this is.
Satmetrix defines World Class Service as: A score with a NPS above 70. The average US company has a Net Promoter Score of 10. Given the NPS range of -100 to +100, a “Positive” score or NPS above 0 is considered “Good”, +50 is “Excellent,” and above 70 is considered “World Class.”