Atlantic City casinos suffered a summer slump in August and it’s all the calendar’s fault.

Figures released Wednesday by the New Jersey Division of Gaming Enforcement show brick-and-mortar gaming revenue at AC’s eight casinos fell 6.7% year-on-year to $229.8m in August. Throw in the $16.1m earned by the casinos’ online gambling sites and August’s year-on-year decline shrinks to 4.9%.

The DGE took pains to point out that August 2015 started on a Saturday, meaning it reaped the benefits of five weekends instead of the standard four. Taking issue with calendar quirks is standard operating procedure for the DGE, which noted that year-to-date gaming revenue is still up 2% to $1.768b.

However you slice it, slot machine revenue was down 5.3% to $167m while table games fared much worse, falling 10.3% to just under $62.8m. Must have been those table-loving millennials who failed to show up because of that missing weekend.