Dubuque casinos report steep revenue declines in August Jeff Montgomery, Telegraph Herald · September 15, 2020 at 8:10 pm Dubuque casinos observed a sharp decline in gambling revenue last month, providing further evidence that the market continues to face major challenges as it attempts to navigate the realities of COVID-19. Diamond Jo and Q casinos collectively produced about $9.3 million in gambling revenue last month, a decline of nearly 13% compared to August 2019. While Diamond Jo earned the majority of the market share, the casino also experienced steeper year-over-year declines. The property reported $5.18 million in gaming revenue last month, a decrease of 16% compared to the same period last year. Casino saw revenues decline of 7.8% to about $4.1 million last month.