HONG KONG -- The total expenditure of Hong Kong residents making personal travel to China's mainland amounted to HK$35.6 billion ($4.59 billion) in 2011, said the Census and Statistics Department on Tuesday.

Of all the trips to the mainland, business travel accounted for about 33 percent while personal travel constituted 67 percent, said the C&SD.

Personal travel refers to travel which is not business-related. It covers travel in package tour mode and non-package tour mode for purposes such as holiday-making, visits to friends and relatives, and attending recreational and cultural activities.

The statistics also showed that Hong Kong residents spent roughly HK$730 per trip, with an average of HK$1,000 for overnight trips and HK$290 for same-day trips.