Forbes released its annual list of NFL team values last week and it shows, as you might have expected, that football teams continue to retain their value. And those values continue to rise.

So much so that the average value for an NFL team is now $1 billion -- a dramatic 19 of 32 teams are valued at more than $1 billion – up from just five in 2007.

The Dallas Cowboys maintained the top spot, valued at $1.6 billion up 7 percent from $1.5 billion in 2007. The rest of the top five are the Washington Redskins ($1.54 billion); New England Patriots ($1.3 billion); Super Bowl Champion New York Giants ($1.2 billion); and New York Jets ($1.2 billion).

The Dolphins rank 13th at $1.04 billion up from 15th and $942 million in 2007. You may recall, Stephen Ross paid $550 million earlier this year for half of the team, of Dolphin Stadium and of the developable land around it.

Sports investment experts say teams are worth what people are willing to pay for them. CNBC Sports Business reporter Darren Rovell breaks down why he thinks NFL teams aren't quite as valuable as Forbes figures.