Slightly more than half of the U.S. public (54%) thinks abortion should be legal in all or most cases, a level that has held fairly stable since the mid-1990s (hovering around 50% on the low end, and reaching no higher than 60%).
About four-in-ten Americans say abortion should be illegal in all or most cases, a level that also has been fairly stable since the mid-1990s.
Source: Aggregated data from Pew Research Center surveys conducted between 2007 and 2012.
Earlier estimates come from averaging yearly ABC/Washington Post polls (1995-2000; 2003-2005);
averaging ABC/Washington Post and ABC/BeliefNet polls (2001); and a February 2006 AP/Ipsos poll.
Question wording can be found here (PDF), and information on the
Pew Research Center's polling methodology can be found here.