Since the market’s re-regulation on 1 January, 60% of Swedes said they had gambled for money in comparison to 66% in 2018.
Gambling participation has dropped 16 percentage points from 2013, when the SGA first carried out the study.
The SGA also found 4% of all online gamblers had played on a site without a Swedish license, while 78% said they had not played on any unlicensed sites.
The SGA has issued a number of fines and warnings since the market’s re-regulation, including the revocation of Global Gaming subsidiary SafeEnt’s license.
As a result of strict regulation, many operators blamed a difficult Swedish market for negative Q3 results.
Gaming Innovation Group (GiG) generated revenue of €30.2m ($33.5m), down 19% year-on-year, attributing the decline to a tough Swedish market.
Betsson Group’s revenue fell 11% to SEK 1.28bn ($132.7m).
Betsson AB CEO Pontus Lindwall said: "As the conditions in Sweden have not been right for large marketing investments, activities have been reduced and reallocated to other markets where they provide better returns."