Please answer the given financial question based on the context.
Context: table of contents celanese purchases of its equity securities information regarding repurchases of our common stock during the three months ended december 31 , 2017 is as follows : period number of shares purchased ( 1 ) average price paid per share total number of shares purchased as part of publicly announced program approximate dollar value of shares remaining that may be purchased under the program ( 2 ) .
|period|totalnumberof sharespurchased ( 1 )|averageprice paidper share|total numberof sharespurchased aspart of publiclyannounced program|approximatedollarvalue of sharesremaining thatmay bepurchased underthe program ( 2 )|
|october 1 - 31 2017|10676|$ 104.10|2014|$ 1531000000|
|november 1 - 30 2017|924|$ 104.02|2014|$ 1531000000|
|december 1 - 31 2017|38605|$ 106.36|2014|$ 1531000000|
|total|50205||2014||
___________________________ ( 1 ) represents shares withheld from employees to cover their statutory minimum withholding requirements for personal income taxes related to the vesting of restricted stock units . ( 2 ) our board of directors has authorized the aggregate repurchase of $ 3.9 billion of our common stock since february 2008 , including an increase of $ 1.5 billion on july 17 , 2017 . see note 17 - stockholders' equity in the accompanying consolidated financial statements for further information. .
Question: what is the total authorized the aggregate repurchase of common stock since february 2008 including the additional amount authorized in 2017 in billions


Answer: The answer is:5.4