Win % between the East and West since 1977.
Between 80 and 89, the East was the powerhouse. And the East owned the 90's, having a higher win percentage in 6 out of the 10 years.
From 2000-2015, the East only had a better win % than the West once (2009) I couidn't find the data for 2016 though 2018, but going by records it looks like it's in the same ballpark as almost every year from 2000 to 2015.
Data like this should be looked at by any fan of the NBA. As it shows how tough the competition was through the playoffs. Getting to the finals in the West, has been much harder, not only because of more tough games during the season, but also the rounds leading to the finals. It gives you a great appreciation for Bird, Jordan, Erving, Thomas for winning in the tough East, and players like Duncan, Kobe/Shaq, Curry winning in the tough West. Can't forget the players who didn't win because of the tough conf they were in, Nash/Amare, Ewing, Wilkins, etc