The 2015 Year in Review at Gallup.com

WASHINGTON, D.C. -- In its efforts to deliver analytics and advice to help leaders solve their most pressing problems, Gallup asks the world what it is thinking on the topics that matter and shares those results on Gallup.com. There was no shortage of important topics in 2015, which proved to be an intriguing, complex and turbulent year: A politically independent Vermont senator surged in the Democratic presidential race, same-sex marriage became law in all 50 states, and Russia's leadership received the lowest approval ratings worldwide for the eighth consecutive year.

The following are among the top stories on Gallup.com for 2015:

The Big Lie: 5.6% Unemployment -- Amid talk of "falling unemployment" in the U.S. fueled by an "economic recovery," Gallup Chairman and CEO Jim Clifton explored what the government's unemployment figure really means and how inaccurate it is in modern-day America.

Sanders Surges, Clinton Sags in U.S. Favorability -- Campaigns for the 2016 presidential election were in full swing in 2015. Some observers coined this past summer the "Summer of Sanders" as favorable ratings doubled for the Democratic socialist from Vermont. Hillary Clinton, who enjoyed high favorability as secretary of state, saw her image tilt negative, her worst rating since December 2007.

75% in U.S. See Widespread Government Corruption -- Three in four Americans in 2014 perceived corruption as widespread in the U.S. government, up from roughly two in three Americans in 2007 and 2009. The trend has been largely stable since 2010, but the percentage of U.S. adults who see corruption as pervasive has not dropped below majority levels in the past decade.

Americans Greatly Overestimate Percent Gay, Lesbian in U.S. -- Same-sex marriage became legal across the U.S. in June. One month earlier, Gallup found that the U.S. public estimated 23% of Americans are gay or lesbian. In reality, the percentage is about 4%. The higher estimate may be attributable to increased media portrayals of gay characters in movies and on television, along with the high-profile legal battle over gay marriage.

In U.S., 58% Back Legal Marijuana Use -- Americans are still very much in favor of legalizing marijuana, as Gallup found continued majority support for such a measure in 2015. Millennials and Generation Xers primarily fueled this support, but many baby boomers also said they favor legalizing marijuana.

Americans Name Government as No. 1 U.S. Problem -- Gallup asks Americans each month to name the most important problem facing the U.S. In March, 18% identified "government" as the nation's top problem, with the economy and unemployment trailing behind. Later in the year, after terrorist attacks in Paris and San Bernardino, California, terrorism topped the list.

Russia Receives Lowest Approval in World; U.S. Highest -- Russia's leadership received the lowest approval ratings worldwide for the eighth consecutive year in 2014. Countries affiliated with the West, particularly NATO countries, soured on Russia dramatically. At the same time, Russians and people in many of its former republics all felt much more negatively about the leadership of the U.S., the EU and Germany. However, U.S. leadership garnered the highest approval ratings worldwide, slightly outpacing Germany.

In U.S., Socialist Presidential Candidates Least Appealing -- Considering a list of various groups, from Catholics to Mormons and gays to Muslims, Americans said in June that a socialist presidential candidate was the least appealing. Forty-seven percent said they would support a socialist for president; all other groups received theoretical majority support.

In U.S., Support for Tea Party Drops to New Low -- Support for the Tea Party movement appeared to drop in October, with only 17% of Americans considering themselves Tea Party supporters. A record 54% said they neither support nor oppose the movement. While the Tea Party's influence may have faded in 2015, this article detailed reasons why this political group may bounce back in the presidential election year.

Pope Francis' Favorable Rating Drops in U.S. -- In advance of his first trip to the U.S., Pope Francis experienced a dip in popularity from the last time Gallup asked Americans about the pontiff in 2014. This drop occurred among both liberals and conservatives, and Catholics and Protestants. On average, Americans still rated Francis more favorably than his predecessor, Pope Benedict XVI.

Employees Want a Lot More From Their Managers -- In April, Gallup reported that one in two U.S. adults have left their job to get away from their manager -- and improve their life overall -- at some point during their career.

Obsolete Annual Reviews: Gallup's Advice -- As the year began winding down, and year-end reviews were in season, Gallup found that many large organizations have experienced the dysfunction of once-a-year performance conversations -- and they're ditching the practice.

Stay with Gallup.com for more discoveries in 2016.