America's obsession with the lottery is growing as jackpots balloon.Monday's $1.6 billion Powerball drawing is the fifth largest pot in U.S. lottery history.And it's part of a trend of growing jackpots. The top five largest have all come in the last three years."The prize gets bigger, it gets bigger, it gets bigger, and it snowballs. More people start playing, it gets even bigger. More people started playing, it gets even bigger and then lo and behold, a couple of weeks go by and you get to a billion dollars," says Jonathan Cohen, author of "For a Dollar and a Dream: State Lotteries in Modern America."RELATED STORY | Powerball players eye $1.5 billion prize, fifth-largest in games record booksCohen says bigger jackpots are by design."The people who run the lottery have made it harder to win because people, people who buy tickets, care a lot more about the size of the jackpot than they do about their odds of winning."In 2015, Powerball increased the range of numbers for the first five white balls, giving players slimmer odds of perfectly matching each number and taking home the grand prize.Higher ticket prices are driving up jackpots, too.Powerball upped prices in 2012 to two dollars per ticket, and in April Mega Millions increased its ticket price to five dollars."A share of every ticket, it depends on sort of over time, it's changed over time. But it's maybe a half or a third of every tick is going to go not just to prizes, but specifically to the top prize," Cohen says.Another factor in enormous jackpots is the Federal Reserve.Lotteries advertise the deferred annuity payment a winner would get if they got paid out over about 30 years. Because the Fed's interest rate has been relatively higher over the past few years, lotteries are able to advertise bigger jackpots."The most important thing is the size of the prize that can go on a billboard," Cohen says. "Any little trick of financial management they can do to project a slightly higher jackpot if you were to take the multi-year annuity, they're going to do it because that's how they know they get people in the door in the first place."RELATED STORY | Small prizes, big risk: How fake sweepstakes emails are stealing money and data ...read more read less