Building the US-Mexico border wall can assist in increasing overall security of the United States by reducing the number of illegal immigrants, as well as, deterring drug and human trafficking. Another reason to build the wall according to supporters is the cost of lost revenue. It is estimated that the United States Internal Revenue Service loses $113 billion a year in lost income tax revenue from illegal immigrants. A third reason, is that it would create employment opportunities and help to lower the current unemployment rate. The final reason is that the National Border Patrol agents are overwhelmed dealing with the large numbers of illegal immigrants flooding into the United States, a border wall would assist to alleviate the manpower burden of protecting the US border.