Diseases of poverty directly correlate with a country's economic performance and wealth distribution: Half of Kenyans live below the poverty level. Preventable diseases like malaria, HIV/AIDS, pneumonia, diarrhoea and malnutrition are the biggest burden, major child-killers, and responsible for much morbidity; weak policies, corruption, inadequate health workers, weak management and poor leadership in the public health sector are largely to blame. According to 2009 estimates, HIV prevalence is about 6.3% of the adult population. However, the 2011 UNAIDS Report suggests that the HIV epidemic may be improving in Kenya, as HIV prevalence is declining among young people (ages 15–24) and pregnant women. Kenya had an estimated 15 million cases of malaria in 2006.