In the below charts, we show a team's win percentage and 'roster noise' (the amount of fluctuation in the team's roster) for every NBA regular season. Roster noise is represented by the amplitude of the curve at a certain data point. For example, the amplitude of the curve for 1987-88 season for the Atlanta Hawks is miniscule since they hardly changed their roster from the previous season. Roster noise is calculated as 100% minus continuity, where continuity is the % of a team's regular season minutes that were filled by players from the previous season's roster.
Roster continuity raw data can be found at Basketball Reference