The September 15, 2018 registration tally for North Carolina is: Democratic 38.02%; Republican 29.85%; Libertarian .52%; Green .01%; Constitution .01%; independent and miscellaneous 31.59%. Here is a link to the State Board of Elections page that shows the numbers. Green and Constitution registration is quite low because until a few months ago, it was not possible for voters to register into those parties and have those registrations tallied.
In February 2018, the percentages were: Democratic 38.65%; Republican 30.17%; Libertarian .50%; independent and miscellaneous 30.68%.
The State Board of Elections has no registration data earlier than 1966. Republicans had always been more numerous than registered independents (in the years for which data exists), until September 2017, when independents started outnumbering Republicans. Back in 1972, North Carolina had 541,916 Republicans but only 79,129 independents.