Lottery is a form of gambling in which numbers are drawn or randomly spit out by machines and prize money is awarded to winners who match the winning combination. It is a form of chance, but its popularity in the United States is often linked to its promise of instant riches and the fact that it allows people to bypass more rigorous financial requirements than are necessary for traditional forms of gambling.

Americans wagered $57.4 billion in lottery tickets last fiscal year, an increase of 9% over the previous year. Most of that is in state-run lotteries. Across the country, the average household spent about $21 on tickets per week in fiscal 2016, according to the North American Association of State and Provincial Lotteries.

One of the reasons the lottery became popular in the immediate post-World War II period is that it allowed states to expand their social safety nets without increasing taxes on lower income households. But that arrangement ended in the 1960s as states began to run out of things to tax and the lottery lost its cachet as a way to raise money for towns, schools, wars and other public works projects.

But there’s more than that to the story of why people play the lottery, including an inextricable human impulse to gamble and a desire for instant wealth. And it’s not just poor people who play, although they do spend a higher percentage of their discretionary income on the tickets. Increasingly, people in the middle and upper quintiles are playing too.