NEW YORK — The share of American households with guns has declined over the past four decades, a national survey shows, with some of the most surprising drops in the South and the Western mountain states, where guns are deeply embedded in the culture.
The gun ownership rate has fallen across a broad cross section of households since the early 1970s, according to data from the General Social Survey, a public opinion survey conducted every two years that asks a sample of American adults if they have guns at home, among other questions.
The rate has dropped in cities large and small, in suburbs, rural areas, and in all regions of the country. It has fallen among households with children, and among those without. It has declined for households that say they are very happy, and for those that say they are not. It is down among churchgoers and those who never sit in pews.
The household gun ownership rate has fallen from an average of 50 percent in the 1970s to 49 percent in the 1980s, 43 percent in the 1990s and 35 percent in the 2000s, according to the survey data, analyzed by The New York Times.
In 2012, the share of American households with guns was 34 percent, according to survey results released on Thursday. Researchers said the difference compared with 2010, when the rate was 32 percent, was not statistically significant.
The findings contrast with the impression left by a flurry of news reports about people rushing to buy guns and clearing shop shelves of assault rifles after the massacre last year at an elementary school in Newtown, Conn.
‘‘There are all these claims that gun ownership is going through the roof,’’ said Daniel Webster, the director of the Johns Hopkins Center for Gun Policy and Research. ‘‘But I suspect the increase in gun sales has been limited mostly to current gun owners. The most reputable surveys show a decline over time in the share of households with guns.’’
Detailed data on gun ownership is scarce. Though some states reported household gun ownership rates in the 1990s, it was not until the early 2000s that questions on the presence of guns at home were asked on a broad federal public health survey of several hundred thousand people, making it possible to see the rates in all states.
But by the mid-2000s, the federal government stopped asking the questions, leaving researchers to rely on much smaller surveys, such as the General Social Survey, conducted by NORC, a research center at the University of Chicago.
Measuring the level of gun ownership can be a vexing problem, with various recent national polls reporting rates between 35 percent and 52 percent. Responses can vary because the survey designs and the wording of questions differ.
But researchers say the survey done by the center at the University of Chicago is crucial because it has consistently tracked gun ownership since 1973, asking if respondents ‘‘happen to have in your home [or garage] any guns or revolvers.’’
The 2012 survey involved interviews with about 2,000 people from March to September and had a margin of sampling error of plus or minus 3 percentage points.
Gallup, which asks a similar question but has a different survey design, shows a higher ownership rate and a more moderate decrease.
No national survey tracks the number of guns within households.
Andrew Arulanandam, a spokesman for the National Rifle Association, said he was skeptical that there had been a decline in household gun ownership. He pointed to reports of increased gun sales, to long waits for gun safety training classes, and to the growing number of background checks, which have surged since the late 1990s, as evidence that ownership is rising.
“I’m sure there are a lot of people who would love to make the case that there are fewer gun owners in this country, but the stories we’ve been hearing and the data we’ve been seeing simply don’t support that,’’ he said.
Tom W. Smith, the director of the General Social Survey, which is financed by the National Science Foundation, said he was confident in the trend.