Dates can be formatted using the ISO 8601 standard as “yyyy-MM-dd”, or using either a 4-digit year or 2-digit year short format for your defined locale. For middle endian locales such as the US these would be “MM/dd/yyyy” or “MM/dd/yy”, for little endian locales these may be “dd/MM/yyyy” and “dd/MM/yy”.
To avoid confusion, you may want to use the least ambiguous format, ISO, and import using yyyy-MM-dd.