So you always read about the inflation rate reported in the news, such as here.
How those numbers are computed anyway?
Every month, the Department of Statistics will actually publish the Consumer Price Index or CPI to reflect the changes of price for various categories of items. Different categories of items have different weighting, and then there is percentage change month over month, year over year.
I am sure that you realize, sometimes the price of food at your local eateries does not conform to this official survey. Well, I would say, use this as a reference only when taking inflation rate into any financial planning endeavour.