When Can We Ask Our Boss For A Raise!!!

Lately i have noticed that price of goods has gone up tremendously.....Oil is one of it,which in a ridiculous price at the moment...I'm talking about normal daily usage stuff - Sugar,Flour etc.....every one claims its due to the hike in the oil price....So I'm asking the million dollar question why isn't our salary increased in the similar way as the price of good's price increase.....after all we are the one buying this stuff....
When will the day come when we can go to our bosses and ask "Boss the price of oil has gone up by USD0.30 per liter...i use per month this amount of oil in order to come to work...can you increase my salary in order to counter this increase ??? when will this day arrive!!!!