Compared with Japan, for the same size of store there are a lot more employees.
Generally there are more staff than customers.
「日本に比べ同じ規模の店舗に対し従業員の数が半端じゃない」＝
"Compared with Japan, for the same size of store there are a lot more employees."
規模 = scale; size
店舗 = shop; store
従業員 = workers; employees; staff
大抵客より多い =
Generally there are more staff than customers.
アメリカ合衆国 
