U.S. data are collected using the Gallup Panel, which is based on a random sample of adults, aged 18 and older, working full time or part time for organizations in the United States, who are members of the Gallup Panel. Gallup uses probability-based, random sampling methods to recruit its Panel members.
In line charts on this webpage, Gallup labels data points with a year and month. Years that have only one data point labeled with the year and "Jan" (abbreviated for "January") reflect annual survey results. Years that have one data point labeled with a specific month besides January or that have multiple data points labeled with specific months reflect results obtained during the noted month(s). When Gallup’s survey field dates for one data point occur in more than one month, Gallup labels the data point with the ending month.