May was a disappointing month for chain restaurants, according to data from TDn2K’s Restaurant Industry Snapshot, which is based on weekly sales from more than 27,000 restaurant units across more than 155 brands.

Same-store sales were down 1.1 percent compared to May of 2016. It also represents a .1 percent drop from April 2017.

Same-store traffic was down 3 percent year over year but was a .2 percentage point improvement from April.

While dine-in sales have been negative in 2017, to-go ordering increased 2.9 percent. Breakfast and mid-afternoon sales offers continued opportunities for growth, according to TDn2K’s report.

Fine dining and quick-serve were the only segments that saw modest gains. Casual dining was down, which was unexpected because the segment had seen gains for the previous four months, according to TDn2K.

Rising staff turnover is adding to restaurant woes. “Many of the brands that we track are already facing unsustainable levels of staffing vacancies,” says Joni Thomas Doolin, TDn2K CEO. “Most alarming is the fact that over 70 percent of employees are leaving voluntarily as opportunities for better work increase.”