The number of Californians leaving the state and moving to Texas is at its highest level in nearly a decade, according to data from the Internal Revenue Service.

According to IRS migration data, which uses individual income tax returns to record year-to-year address changes, over 250,000 California residents moved out of the state between 2013 and 2014, the latest period for which data was available. The tax returns reported more than $21 billion in adjusted gross income to the IRS.

Of the returns, 33,626 reported address changes from California to Texas, which has been the top destination for individuals leaving California since 2007. Californians who moved to Texas between 2013 and 2014 reported $2.19 billion in adjusted gross income.

The number of returns showing address changes from California to Texas hasn’t been this high since the period 2006-07. During that period, 34,078 returns were filed showing address changes to Texas.

Fewer Texans moved to California during the 2013-14 period. The IRS reported 21,391 returns with address changes from Texas to California. The returns reported $1.56 billion in adjusted gross income.

"California’s taxes and regulations are crushing businesses, and there are more opportunities in Texas for people to start new companies, get good jobs, and create better lives for their families," said Nathan Nascimento, the director of state initiatives at Freedom Partners. "When tax and regulatory climates are bad, people will move to better economic environments—this phenomenon isn’t a mystery, it’s how marketplaces work. Not only should other state governments take note of this, but so should the federal government."

According to Tom Gray of the Manhattan Institute, people may be leaving California for the employment opportunities, tax breaks, or less crowded living arrangements that other states offer.

"States with low unemployment rates, such as Texas, are drawing people from California, whose rate is above the national average," Gray wrote. "Taxation also appears to be a factor, especially as it contributes to the business climate and, in turn, jobs."

"Most of the destination states favored by Californians have lower taxes," Gray wrote. "States that have gained the most at California’s expense are rated as having better business climates. The data suggest that may cost drivers—taxes, regulations, the high price of housing and commercial real estate, costly electricity, union power, and high labor costs—are prompting businesses to locate outside California, thus helping to drive the exodus."