Asia Foundation's Survey of the Afghan People 2011
Growing insecurity was the main reason for increasing pessimism, the group found. It began Afghan polling in 2004.
The 2011 survey found more people satisfied with education, water and health provision than before.
Sympathy for armed militant groups such as the Taliban fell to 29% from 40% in 2010, the lowest level recorded by the Asia Foundation.
The survey also showed considerable public support for efforts to reach out and make peace with militant groups.
The findings come just months after a UN report said there had been a considerable rise in violent incidents in Afghanistan this year, particularly in the south and south-east.
The Asia Foundation survey appeared to reflect this, with residents of those areas expressing the highest degree of uncertainty.
The survey interviewed more than 6,300 Afghan citizens across all of the country's 34 provinces.
Doubt cast over glowing Afghan survey - Aljazeera
As U.S. Prepares to Exit, Poll Shows Afghan Public Fearful for Its Safety -- and Democracy's Demands - NPR
Reflecting on Afghan public opinion - The Nation (Pakistan)