The oil-rich Gulf state of Kuwait had accumulated reserves of $548 billion as of June 30 after continued growth in the first six months of 2014, a local daily reported Sunday.

The reserves are invested in two state funds, the State Reserve Fund with $149 billion and the Reserve Fund for Future Generations with $399 billion, Al-Qabas newspaper said, citing a report by the Audit Bureau, Kuwait's state accounting watchdog.

Both funds are run by the Kuwait Investment Authority, the country's sovereign wealth fund.

The report said the reserves had increased by $15.7 billion in the first six months of the year.

Kuwaiti authorities have not officially disclosed the amount of their reserves, but estimates had put them at around $500 billion at the end of March this year.

Kuwait, which says it sits on around 10 percent of global crude reserves and pumps around three million barrels per day, has posted a budget surplus in each of the past 15 fiscal years. Oil income makes up 94 percent of public revenues.

After first deducting 10 percent of revenues for its sovereign wealth fund, that percentage was increased to 25 percent in the last two fiscal years.

The tiny emirate has a native population of 1.25 million and is also home to about 2.8 million foreigners.