item 7 . management 2019s discussion and analysis of financial condition and results of operations the following discussion of historical results of operations and financial condition should be read in conjunction with the audited financial statements and the notes thereto which appear elsewhere in this report . overview on april 12 , 1999 , pca acquired the containerboard and corrugated products business of pactiv corporation ( the 201cgroup 201d ) , formerly known as tenneco packaging inc. , a wholly owned subsidiary of tenneco , inc . the group operated prior to april 12 , 1999 as a division of pactiv , and not as a separate , stand-alone entity . from its formation in january 1999 and through the closing of the acquisition on april 12 , 1999 , pca did not have any significant operations . the april 12 , 1999 acquisition was accounted for using historical values for the contributed assets . purchase accounting was not applied because , under the applicable accounting guidance , a change of control was deemed not to have occurred as a result of the participating veto rights held by pactiv after the closing of the transactions under the terms of the stockholders agreement entered into in connection with the transactions . results of operations year ended december 31 , 2005 compared to year ended december 31 , 2004 the historical results of operations of pca for the years ended december , 31 2005 and 2004 are set forth the below : for the year ended december 31 , ( in millions ) 2005 2004 change .

Table:
( in millions ) | for the year ended december 31 , 2005 | for the year ended december 31 , 2004 | change
net sales | $ 1993.7 | $ 1890.1 | $ 103.6
income before interest and taxes | $ 116.1 | $ 140.5 | $ -24.4 ( 24.4 )
interest expense net | -28.1 ( 28.1 ) | -29.6 ( 29.6 ) | 1.5
income before taxes | 88.0 | 110.9 | -22.9 ( 22.9 )
provision for income taxes | -35.4 ( 35.4 ) | -42.2 ( 42.2 ) | 6.8
net income | $ 52.6 | $ 68.7 | $ -16.1 ( 16.1 )
net sales net sales increased by $ 103.6 million , or 5.5% ( 5.5 % ) , for the year ended december 31 , 2005 from the year ended december 31 , 2004 .
net sales increased primarily due to increased sales prices and volumes of corrugated products compared to 2004 .
total corrugated products volume sold increased 4.2% ( 4.2 % ) to 31.2 billion square feet in 2005 compared to 29.9 billion square feet in 2004 .
on a comparable shipment-per-workday basis , corrugated products sales volume increased 4.6% ( 4.6 % ) in 2005 from 2004 .
excluding pca 2019s acquisition of midland container in april 2005 , corrugated products volume was 3.0% ( 3.0 % ) higher in 2005 than 2004 and up 3.4% ( 3.4 % ) compared to 2004 on a shipment-per-workday basis .
shipments-per-workday is calculated by dividing our total corrugated products volume during the year by the number of workdays within the year .
the larger percentage increase was due to the fact that 2005 had one less workday ( 250 days ) , those days not falling on a weekend or holiday , than 2004 ( 251 days ) .
containerboard sales volume to external domestic and export customers decreased 12.2% ( 12.2 % ) to 417000 tons for the year ended december 31 , 2005 from 475000 tons in 2004. .

Question: what was total interest expense in millions in 2005 and 2004?
Answer: 57.7
Calculation: add(28.1, 29.6)