I just looked at Howmanyleft site - which clearly isn't a guarantee to be correct data - but assuming the V1 was up to Q3 in 2014 - there were 97 Nismo's on the road. Assuming perhaps the odd one was a V2 in that number. After Q1 in 2015 the number was 164. So a growth of 67.
I sort of expected the V2 to far out-sell the V1 - but it seems the sales levels are not far off each other.
Interesting. Suggests there are 1892 - 370z's on the Road.... Not sure what the actual number is.