Advertisers at Super Bowl 50 are expecting to reach the event’s largest-ever audience, as some sources estimate that as many as 189 million people will watch the NFL’s championship game.

But to reach that market, more than half of the entire United States population, companies are going to have to ante up. The average estimated cost of a 30-second commercial to air during the Super Bowl is $5 million, Forbes reported, up from $4.4 million for ads during Super Bowl 49, in 2015.

That price spike is the continuation of a more than decade-long trend, and one that is showing no sign of slowing down.

Average Super Bowl ad prices jumped 76 per cent between 2006 and 2015, according to a study from Kantar Media. In 2006, a 30-second ad cost about $2.5 million, and by 2015 had jumped to $4.4 million.

The total amount spent on Super Bowl advertising has surged even more quickly. In 2006, advertisers spent roughly $162.5 million on ads, compared to $345.4 million in 2015, a 112.4 per cent increase.

The average cost of a 30 second advert has reached $5m

The good news for the advertisers is that the majority of people watching the Super Bowl are interested more in the ads than in the game between he Denver Broncos and Carolina Panthers.

A 2012 study by California ad agency Venables Bell & Partners found that 78 per cent of Americans prefer the Super Bowl commercials to the actual game.