The National Statistics Institute confirms Spain's economy grew at its fastest rate in six years in the first quarter thanks to increased domestic demand.

Presenting final figures for the quarter Thursday, the institute said the economy expanded by 0.4 percent in January through March, the best quarter since the first three-month period of 2008, when the economy grew 0.5 percent.

The institute adjusted the year-on-year rate downward to 0.5 percent from 0.6 percent, the first annual growth figure after nine quarters of contraction.

The government says Spain's economy should grow by 1.2 percent in 2014 and 1.8 percent in 2015.

The country fell into the first of two severe recessions in the second half of 2008 after its real estate sector collapsed. It emerged from the second slump late 2013.