Party affiliation in the USA

This morning, NPR was mentioning that, among Republicans, Trump still enjoyed some major support.

This prompted me to think, what's today's party affiliation in the United States?

I obviously had some idea with something like 1/3 – 1/3 – 1/3, between Republicans, independents, and Democrats. Gallup got me a more precise set of numbers, like respectively 27, 43, 29, giving Democrats a slight edge.

This edge is even magnified if we looked at how independents would tip the balance if their preference is taken into account with 42% leaning republican vs. 47% leaning democrat.

This could be deemed as an encouraging sign prior to the November 2018 election, but with the mercurial Trump, data vary daily...