As the majority of people infected with HIV are unaware of their status, it is reasonable to expect that there may be significant cases of under-reporting and inaccuracies in certain listed statistics. Estimates may vary wildly between source or between years as old information is discarded and new information is acquired.[citation needed] Documented cases lists do not give an accurate description of the epidemic, but do attempt to quantify actual known cases, as well as documented cumulative impact.