SIOUX FALLS, S.D. (KELO AM) - According to a report from George Mason University, the apartment industry in South Dakota had an economic impact of over $2 billion dollars in 2011.     The Executive Director of the South Dakota Multi Housing Association of South Dakota, Dan Siefken, says the multi housing industry spent $47 million statewide on apartment construction.     Siefken says that generated almost $80 million dollars in supporting 785 jobs.     And South Dakota's over 75,000 apartment residents spent almost $870,000 on goods and service creating an impact of $1.8 billion dollars supporting 47,000 jobs.     Siefkin says the eye-opening report show just how important apartments and their residents are to South Dakota's economy.