Perhaps Toyota is faced with the same increases in energy costs that we have - or maybe they need to raise funds to give their employees a pay raise. Heck, maybe they are planning on investing in another plant due to increased demand, and thus need to raise capital.
At the low end model this is only about a 2.25% increase, which sounds more like an adjustment for inflation.
(Of course, I opted for a $13k corolla that gets about 35mpg - If I'm gonna spend $25k to $40k on a vehicle its gonna at least be a plug-in hybrid!)