Variable interest rate tables are tables in which the interest rate is a scalar rate published monthly.  One example is the 30-Year Treasury Rates table. The format ProAdmin expects for this type of table is year (between 1900 and 2200, inclusive), month (between 1 and 12, inclusive), and rate (between 0 and 1, inclusive).  A value must be specified for each month even if it is the same as that of the prior month. Below are examples of a .csv and .txt file in the structure expected for a variable interest rate.