• by Laurie Sullivan  @lauriesullivan, March 24, 2016

From April 2015 through February 2016, YouTube site visitors have spent 485% more time watching candidate- and issue-related videos, with nearly 50% of that time occurring on mobile -- up 548% since YouTube began tracking the trend data released Thursday.

Key political moments determine the amount of time people spend on YouTube searching and watching policy-related videos. Controversial and provocative debates during this year's U.S. presidential campaign appear to have led voters to seek out more information about candidates on YouTube.

Issues-related YouTube searches have grown since the presidential candidates began announcing their runs for office, according to YouTube.

Refugees, immigration, gun control, economy and health care are some of the searched-for topics. Among these, the topic of refugees has seen the largest growth since April 2015 -- three times more than the next-highest.

A variety of age groups have turned more toward video for information. While 59% of people who turn to online video on YouTube to learn more about the candidates are under the age of 35, data also suggests that an older audience uses online video as a resource. More than one in four are over the age of 45, while some 15% are between the ages of 34 and 44, 13% are between 45 and 54, and 13% are at least 55 years of age.

Key political and cultural moments often shape the amount of time that voters will spend on YouTube watching candidate- and issue-related videos. Looking at key moments like the legalization of marriage, the Iowa Caucus and recent GOP and Democratic debates, there were significant increases in the amount of time around each moment.

For example, the week after same-sex marriage was legalized, the amount of time people spent on YouTube watching related videos rose 24 times the average of the three weeks prior. The first spike was driven mainly by videos discussing the ruling and the second by reaction videos, such as Fine Brothers’ “Kids React to Gay Marriage Ruling, according to the YouTube data.

Candidates took advantage of the increase in the time that YouTube visitors spent viewing videos. Advertising on YouTube from candidates rose heading into the caucuses and primaries. Since October, paid views rose 294%, accounting for 77% of total paid views to date, according to the data.

The touchy race and tight competition in early caucus and primary states led the candidates to buy more advertising inventory on YouTube. YouTube essentially sold out of reserve ad inventory ahead of Iowa, New Hampshire, South Carolina and Nevada caucuses and primaries. This was a first for the early causes and primary states of Iowa and New Hampshire.