l National Consumer Price Index 2018
In order to determine the payment of the contributions and their accessories, the national consumer price index (INPC) published by the National Institute of Statistics and Geography and Informatics (INEGI) is used and published in the Official Gazette of the Federation within the first ten days of the month following that corresponding.
| Month | Indexes | Publishing date on DOF |
| January | *131.508 | February 09, 2018 |
| February | *132.009 | March 09, 2018 |
| March | *132.436 | April 10, 2018 |
| April | *131.987 | May 10, 2018 |
| May | *131.773 | June 08, 2018 |
* *The Bank of Mexico, with the participation of INEGI, has resolved updating the basis of the National Consumer Price Index and the methodologies that are used for compiling it. The reference period is the second two-week period of December 2010.
Source: sat.gob.mx