Seasonal adjustment: Data are not seasonally adjusted.
Item baskets and the weights are updated at the end of every year and chained with the Laspeyres formulation. Every year in December new goods and services are added in the basket, goods and services which lost their importance are taken out and renewed weights are used in the calculation of index. Index is calculated by dividing current prices to the prices of previous December, which is “new price reference period (po)”, and then chained by multiplying it with the index numbers of December.
I = w . Pi /
I : index
Pi : current price
w : weight
It = wı . Pit / PDecember(t-1) . IDecember(t-1)
wı : new weight
t : time
Geometric average is used for the computations of commodity prices from commodity
Sources: Household Budget Survey, Institutional Population Expenditure Survey, Tourism Survey and administrative data.