Over 80 percent of houses in the United States have banned smoking within their walls.

The Center for Disease Control (CDC) said in a recently released report that these numbers have gone up drastically in the last 20 years. This increase in banned smoking is present in both non-smoking and smoking households. In fact, the greatest increase has been seen among smoking households.

Published in the Morbidity and Mortality Weekly Report on Sept. 5, the report gathered statistic through a survey covering tobacco use habits.

In the early 90’s, only 43 percent of families had no smoking rules enforced in their homes. That number jumped to 83 percent by 2011.

Two decades ago, close to 58 percent of non-smoking homes had banned tobacco use inside. Now that number is 91.4 percent.

But smoking households have shown the most dramatic increase. The number of smoking households that have moved the practice outside has reached 46 percent, showing that five times more houses with smokers are smoke free than they were 20 years ago.

Health officials consider this a tremendous move in the right direction. The increased number of people who smoke outside of their homes means that more family members and visitors can avoid exposure to secondhand smoke.

The CDC says that secondhand smoke is comprised of over 7,000 different chemicals, dozens of which cause cancer.

Shifting social norms and effective legislation have been credited with the hike in smoke-free homes. Information about the harmful effects of secondhand smoke have circulated well and laws banning smoking inside public areas have taken hold.

When laws prohibiting smoking in restaurants, bars, and other public areas were first introduced, there was some worry that the laws would simply drive more people to stay home and smoke in their houses. The statistics from this report indicate that is not what really happened.

“People no longer see it as acceptable to expose nonsmokers to secondhand smoke,” said lead author of the study, Brian King.