Back to Top

 Skip navigation

Background Notes

Wholesale Price Index        

The term Industrial Producer Price Index refers to a family of indices that measure the average change over time in the selling prices received by domestic producers of goods and services. The other three wholesale price index series incorporate imported and home produced goods sold by manufacturers and wholesale outlets.


The output price indices for sectors of Manufacturing Industries cover both home sales and export sales.  The Indices for Total transportable goods industries; Food, drink and tobacco; Manufacturing industries excluding food; Manufacturing industries excluding food, drink and tobacco; Intermediate goods industries (except energy); Capital goods industries; Durable consumer goods industries; Non-durable consumer goods industries; Manufacturing industries (home sales); Manufacturing industries (export sales) and Total manufacturing industries are all calculated on a net sector basis, i.e. the weights used to combine the sectoral indices (including those for sectors not distinguished in Table 2) exclude sales to other sectors of Manufacturing Industry.

Table 2A gives the percentage contribution of each sector (including those not published on Table 2) to the overall percentage change on Table 2. The percentage contributions on Table 2A may not add up to the Total Manufacturing industries percentage change on Table 2 due to rounding and other adjustments for presentational purposes.  In comparing these contributions against these percentage changes in indices presented on Table 2 caution should be exercised as the former is calculated on a net sector basis.

The Building Materials, Capital Goods and Energy Products indices (Tables 3, 4 and 5) cover home production and imports of these commodities.  Table 3, the Wholesale Price Index for Building and Construction Materials, provides only a general indication of price trends in that sector.  Actual transaction prices are collected for materials purchased by construction and civil engineering firms. The price indices reflect an ‘average’ over a mixture of products from many companies throughout the country.  They also reflect prices for both long-term and short-term contracts and for high and low volume civil engineering works. It should be noted that long-term, high volume fixed contracts for major works might dilute in the short-term the impact of emerging price changes on the index.  Furthermore, industry sources have confirmed that price increases notified by companies may not always be achieved in practice following negotiations. Much depends on the prevailing market conditions. Therefore changes over the short-term in the indices derived from these transaction prices will not always coincide with price changes notified by companies.


All indices in the series are based on prices at the 15th of the month. Quarterly and annual indices are simple averages of the corresponding monthly indices.

Prices used in the compilation of the indices are:

  • excluding delivery charges itemised on the invoice separately
  • after discounts or surcharges are applied
  • before addition of direct subsidies
  • exclusive of VAT (except for private vehicles used in Table 4)
  • inclusive of excise duty

Every effort is made by the Wholesale Prices Section to collect all prices for the relevant month. Where this is not possible late prices are included in the following month’s calculations.


This Wholesale Price Index series is compiled to base 2015 = 100. A methodological description of this updated series is given in the Revised Wholesale Price Index Introduction to Series 2015=100.

Calculating percentage changes in the index

The movement of the output price indices is expressed as percentage change, rather than a change in index points, because index point changes are affected by the level of the index in relation to its base period, whereas percentage changes are not.

The example below illustrates the computation of a percentage change:

Percentage change calculation


Current index


Less previous index


Equals in index points 


Divided by the previous index 




Results multiplied by 100 

 0.0343 x 100

Equals percentage change 


Alternatively, users may calculate a percentage change by dividing the current index by the previous index, multiplying by 100 and then subtracting 100.