After 4 to 5 Months, Many Job Seekers Abandon Search
On average "unemployed individuals were jobless for about 20 weeks in 2010 before giving up their job search and leaving the labor force," according to a 2011 analysis of BLS data.
Ilg, R. (2011). How long before the unemployed find jobs or quit looking? (Issues in Labor Statistics, Summary No. 11-1). Washington, DC: Bureau of Labor Statistics. Retrieved from http://www.bls.gov/opub/ils/pdf/opbils89.pdf