Australia Asylum statistics By sjpillow Jan 1, 2010 Irregular maritime arrivals (IMAs) in 2010:134 boats carrying 6,535 people irregularly arrived at Australia Period: Jan 1, 2010 to Apr 21, 2011 the number of irregular maritime arrivals in Australia Apr 19, 2011 16 boats carrying 921 people irregularly arrived at Australia Apr 20, 2011 4,552 IMAs detained on the mainland, 1,748 on Christmas Island Apr 21, 2011 Currently 392 detainees in Villawood of whom 172 are IMAs