The index measures the monthly evolution of the volume of industrial production (excluding construction). Since January 2009 the indices have been calculated with reference to the base year 2005 using the new Ateco 2007 classification (Italian edition of Nace Rev. 2).
In April 2011 the industrial production index seasonally adjusted increased by 1.0% compared with the previous month. The percentage change of the average of the last three months with respect to the previous three months increased by 1.1.
The calendar adjusted industrial production index increased by 3.7% compared with April 2010 (calendar working days being 20 versus 21 days in April 2010); in the period January-April 2011 the percentage change was +2.5 compared with the same period of 2010.
The unadjusted index of industrial production decreased by 0.1% compared with April 2010.