>>715260625not really sure how accurate those sales numbers are but for the ones i found are
Need for Speed: Underground - 15 million+
Need for Speed: Underground 2 - 11 million+
Need for Speed: Most Wanted - 17.8 million
Need for Speed: Carbon - 15.6 million
Need for Speed: ProStreet - 10.9 million
Need for Speed: Undercover - 8.9 million
Need for Speed: Hot Pursuit - 5 million+
Need for Speed Rivals - 4 million+
Need for Speed: No Limits - 3-4 million
Need for Speed - 3-4 million
Need for Speed Payback - 3-4 million
Need for Speed Heat - 3-4 million
according to vg charts, but the other source vary greatly.
All i know is that from underground to carbon people were all over NFS, then the series slowly dwindled