College savings plans, commonly known as 529 plans, surged into the news recently when President Obama proposed, then retreated from, a plan to tax investment returns on new contributions.

Since distributions became tax-free in the early 2000s, college savings plans have grown in popularity, and all but one state currently operates some form of 529 plan. Bipartisan pressure from both sides of the political aisle and the popularity of 529 plans were major factors in the president’s reversal.

Here are a few quick facts about 529 plans.

• There are two main types of 529 plans: prepaid tuition plans and college savings plans. Prepaid tuition plans allow families to buy tuition credits at today’s prices to be used in the future. College savings plans function like 401(k) retirement plans where contributions grow tax free as long as withdrawn funds are used for higher education expenses.
• During the last 15 years, the amount invested in 529 plans has grown rapidly. In 2000, families invested a total of $9.29 billion in 529 plans. By the middle of 2014, the amount invested had increased to a record level of $244.5 billion according to the College Savings Plans Network.
• Forty-nine states and the District of Columbia offer a 529 plan. Thirty-eight states offer only a college savings plan, one state offers only a prepaid tuition plan, and 10 states offer both types of 529 plans.
• Under current tax law, withdrawn funds used for college expenses are free from federal income taxes.
• At least 33 states offer an income tax credit or deduction for contributions to state sponsored 529 plans.
• At least 12 states have matching grant programs to incentivize low- and middle-income families to participate in 529 plans.