A 2002 US study by the National Institute on Alcohol Abuse and Alcoholism (NIAAA) showed that 17.7 percent of individuals diagnosed as alcohol dependent more than one year prior returned to low-risk drinking. This group, however, showed fewer initial symptoms of dependency.[134] A follow-up study, using the same subjects that were judged to be in remission in 2001–2002, examined the rates of return to problem drinking in 2004–2005. The study found abstinence from alcohol was the most stable form of remission for recovering alcoholics.[135] A long-term (60 year) follow-up of two groups of alcoholic men concluded that "return to controlled drinking rarely persisted for much more than a decade without relapse or evolution into abstinence."[136]