The export price of biscuit increased from 2004 to 2008 by how much percent?

From the level of 2004 percentage increase in export price in 2008 = (Price in 2008 - price in 2004) x 100/price in 2004
From the level of 2004 percentage increase in export price in 2008 = (500 - 150) x 100/150 = 233¹/₃%