Raleigh-Cary is the only MSA over 1M to be among the fastest growing MSAs in the nation. Wake added the 5th largest number of people among all counties in the USA.
While I haven’t yet been able to put my fingers on any other county data for the Triangle, I did find this color growth chart. It looks like the Raleigh MSA is still outpacing the Durham MSA in growth rates.
In NC in general, Wake and Mecklenburg continue to do the heavy lifting and so do the Charlotte and Raleigh MSAs. The Wilmington area continues to grow rapidly, but their population base is still pretty small in comparison.