Total revenue in the four weeks to April 25 totalled $895,299, down from $966,752 in March.
Consumer spending on sports betting also fell 16.7% from $6.6m in March to $5.5m in April, with players winning $4.4m in the process.
Year-on-year comparisons are not possible as the Delaware Lottery did not publish figures in April 2020 due to the closure of all retail sportsbooks due to the novel coronavirus (Covid-19). Delaware currently only permits land-based sports betting.
Delaware Park retained top spot in the state with $514,951 in sports betting revenue, as players wagered $3.2m at the facility during April.