zimmer holdings , inc .
2013 form 10-k annual report notes to consolidated financial statements ( continued ) state income tax returns are generally subject to examination for a period of 3 to 5 years after filing of the respective return .
the state impact of any federal changes generally remains subject to examination by various states for a period of up to one year after formal notification to the states .
we have various state income tax returns in the process of examination , administrative appeals or litigation .
our tax returns are currently under examination in various foreign jurisdictions .
foreign jurisdictions have statutes of limitations generally ranging from 3 to 5 years .
years still open to examination by foreign tax authorities in major jurisdictions include : australia ( 2009 onward ) , canada ( 2007 onward ) , france ( 2011 onward ) , germany ( 2009 onward ) , ireland ( 2009 onward ) , italy ( 2010 onward ) , japan ( 2010 onward ) , korea ( 2008 onward ) , puerto rico ( 2008 onward ) , switzerland ( 2012 onward ) , and the united kingdom ( 2012 onward ) .
16 .
capital stock and earnings per share we are authorized to issue 250 million shares of preferred stock , none of which were issued or outstanding as of december 31 , 2013 .
the numerator for both basic and diluted earnings per share is net earnings available to common stockholders .
the denominator for basic earnings per share is the weighted average number of common shares outstanding during the period .
the denominator for diluted earnings per share is weighted average shares outstanding adjusted for the effect of dilutive stock options and other equity awards .
the following is a reconciliation of weighted average shares for the basic and diluted share computations ( in millions ) : .

For the Years Ended December 31,
2013
2012
2011
Weighted average shares outstanding for basic net earnings per share
169.6
174.9
187.6
Effect of dilutive stock options and other equity awards
2.2
1.1
1.1
Weighted average shares outstanding for diluted net earnings per share
171.8
176.0
188.7

weighted average shares outstanding for basic net earnings per share 169.6 174.9 187.6 effect of dilutive stock options and other equity awards 2.2 1.1 1.1 weighted average shares outstanding for diluted net earnings per share 171.8 176.0 188.7 for the year ended december 31 , 2013 , an average of 3.1 million options to purchase shares of common stock were not included in the computation of diluted earnings per share as the exercise prices of these options were greater than the average market price of the common stock .
for the years ended december 31 , 2012 and 2011 , an average of 11.9 million and 13.2 million options , respectively , were not included .
during 2013 , we repurchased 9.1 million shares of our common stock at an average price of $ 78.88 per share for a total cash outlay of $ 719.0 million , including commissions .
effective january 1 , 2014 , we have a new share repurchase program that authorizes purchases of up to $ 1.0 billion with no expiration date .
no further purchases will be made under the previous share repurchase program .
17 .
segment data we design , develop , manufacture and market orthopaedic reconstructive implants , biologics , dental implants , spinal implants , trauma products and related surgical products which include surgical supplies and instruments designed to aid in surgical procedures and post-operation rehabilitation .
we also provide other healthcare-related services .
we manage operations through three major geographic segments 2013 the americas , which is comprised principally of the u.s .
and includes other north , central and south american markets ; europe , which is comprised principally of europe and includes the middle east and african markets ; and asia pacific , which is comprised primarily of japan and includes other asian and pacific markets .
this structure is the basis for our reportable segment information discussed below .
management evaluates reportable segment performance based upon segment operating profit exclusive of operating expenses pertaining to share-based payment expense , inventory step-up and certain other inventory and manufacturing related charges , 201ccertain claims , 201d goodwill impairment , 201cspecial items , 201d and global operations and corporate functions .
global operations and corporate functions include research , development engineering , medical education , brand management , corporate legal , finance , and human resource functions , u.s. , puerto rico and ireland-based manufacturing operations and logistics and intangible asset amortization resulting from business combination accounting .
intercompany transactions have been eliminated from segment operating profit .
management reviews accounts receivable , inventory , property , plant and equipment , goodwill and intangible assets by reportable segment exclusive of u.s. , puerto rico and ireland-based manufacturing operations and logistics and corporate assets. .

Question: Analyse this data from a financial earnings document. what was the change in millions of weighted average shares outstanding for diluted net earnings per share between 2012 and 2013?
Choices:
-4.2
1
-15.8
-4200000
12.7
Correct choice index: 0