More than 80 percent of the public believes that poor access to treatment for mental illness, illegal gun deals, family instability, and domestic violence are responsible for mass shootings, a new poll shows.

The poll, by Morning Consult and Politico, reveals public attitudes shortly after several school shootings this year. More than 70 percent of voters believed other factors played a somewhat or significant role in mass shootings, including substance abuse, lack of morality in U.S. culture, peer pressure, and the amount of media attention paid to gun violence.

Factors that came behind these, but were blamed at least to a certain degree by a majority of voters, were lack of economic opportunity, legal gun purchases, and gun violence in movies, TV, and video games.

The poll reveals that the public was equally divided on whether the National Rifle Association shares any blame for the shootings. More people believe that Republicans in Congress share some level of blame for mass shootings compared to Democrats. Forty-three percent believe Republicans are to blame and 33 percent blame Democrats. Forty percent blame President Trump.

The polling shows that 38 percent of people live in homes where a gun is present, and 67 percent support stricter gun control laws.

Among respondents, 45 percent said they had strong support for stricter gun laws and 16 percent strongly oppose them. A slightly larger number, 46 percent compared with 42 percent, believed it was more important to protect citizens' rights to own guns than to limit that right.

The U.S. has faced several recent school shootings. In May, a gunman killed 10 people at a high school in Sante Fe, Texas, and in February 17 people were killed in a mass shooting in Parkland, Fla. Both gunmen had a history of troubling behavior, but mental health experts stress that people undergoing treatment for mental illness aren't violent and are more likely to be victims of abuse than perpetrators.

The poll was conducted over the phone between May 18 and 22 and surveyed 1,993 registered voters.