Besides your claims/losses, premium are also driven by your Property Values and Sales. Even if rates were flat/same in a given year, if your Restaurants Building/Contents are worth more vs. last year and/or your Sales have risen, then you should expect that minimum % increase in your premium.
For example, lets' use your homeowners insurance as many understand this best. If your homes value goes up 10% in a given year and thus you increased the value of your home with your insurance company by 10%, your homeowners premium would rise at least 10%.