For more information, please see the Import/Export Price Indexes frequently asked questions site at http://www.bls.gov/mxp/ippfaq.htm. **DISCONTINUED**
Source: US. Bureau of Labor Statistics
Release: U.S. Import and Export Price Indexes
US. Bureau of Labor Statistics, Import (Harmonized System): Salt, sulfur, earths and stone, plaster materials, lime and cement (DISCONTINUED SERIES) [IP25], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/IP25/, August 31, 2015.