equity compensation plan information the plan documents for the plans described in the footnotes below are included as exhibits to this form 10-k , and are incorporated herein by reference in their entirety .
the following table provides information as of dec .
31 , 2006 regarding the number of shares of ppg common stock that may be issued under ppg 2019s equity compensation plans .
plan category securities exercise of outstanding options , warrants and rights weighted- average exercise price of outstanding warrants and rights number of securities remaining available for future issuance under equity compensation ( excluding securities reflected in column ( a ) ) equity compensation plans approved by security holders ( 1 ) 9413216 $ 58.35 10265556 equity compensation plans not approved by security holders ( 2 ) , ( 3 ) 2089300 $ 70.00 2014 .

<i>Plan category</i>
<i>Numberof securities to be issued upon exercise of outstanding options, warrants and rights</i>  <i></i> <i></i> ( <i></i> a <i></i> ) <i></i>
<i></i> Weighted- average exercise price of outstanding options, warrants and rights <i></i> <i>(b)</i>
<i>Number of securities remaining available for future issuance under equity compensation plans (excluding securities reflected in column (a))</i>  <i></i> <i></i> (c) <i></i>
Equity compensation plans approved by security holders<sup>(1)</sup>
9,413,216
$58.35
10,265,556
Equity compensation plans not approved by security holders<sup>(2), (3)</sup>
2,089,300
$70.00
—
Total
11,502,516
$60.57
10,265,556

( 1 ) equity compensation plans approved by security holders include the ppg industries , inc .
stock plan , the ppg omnibus plan , the ppg industries , inc .
executive officers 2019 long term incentive plan , and the ppg industries inc .
long term incentive plan .
( 2 ) equity compensation plans not approved by security holders include the ppg industries , inc .
challenge 2000 stock plan .
this plan is a broad- based stock option plan under which the company granted to substantially all active employees of the company and its majority owned subsidiaries on july 1 , 1998 , the option to purchase 100 shares of the company 2019s common stock at its then fair market value of $ 70.00 per share .
options became exercisable on july 1 , 2003 , and expire on june 30 , 2008 .
there were 2089300 shares issuable upon exercise of options outstanding under this plan as of dec .
31 , 2006 .
( 3 ) excluded from the information presented here are common stock equivalents held under the ppg industries , inc .
deferred compensation plan , the ppg industries , inc .
deferred compensation plan for directors and the ppg industries , inc .
directors 2019 common stock plan , none of which are equity compensation plans .
as supplemental information , there were 491168 common stock equivalents held under such plans as of dec .
31 , 2006 .
item 6 .
selected financial data the information required by item 6 regarding the selected financial data for the five years ended dec .
31 , 2006 is included in exhibit 99.2 filed with this form 10-k and is incorporated herein by reference .
this information is also reported in the eleven-year digest on page 72 of the annual report under the captions net sales , income ( loss ) before accounting changes , cumulative effect of accounting changes , net income ( loss ) , earnings ( loss ) per common share before accounting changes , cumulative effect of accounting changes on earnings ( loss ) per common share , earnings ( loss ) per common share , earnings ( loss ) per common share 2013 assuming dilution , dividends per share , total assets and long-term debt for the years 2002 through 2006 .
item 7 .
management 2019s discussion and analysis of financial condition and results of operations performance in 2006 compared with 2005 performance overview our sales increased 8% ( 8 % ) to $ 11.0 billion in 2006 compared to $ 10.2 billion in 2005 .
sales increased 4% ( 4 % ) due to the impact of acquisitions , 2% ( 2 % ) due to increased volumes , and 2% ( 2 % ) due to increased selling prices .
cost of sales as a percentage of sales increased slightly to 63.7% ( 63.7 % ) compared to 63.5% ( 63.5 % ) in 2005 .
selling , general and administrative expense increased slightly as a percentage of sales to 17.9% ( 17.9 % ) compared to 17.4% ( 17.4 % ) in 2005 .
these costs increased primarily due to higher expenses related to store expansions in our architectural coatings operating segment and increased advertising to promote growth in our optical products operating segment .
other charges decreased $ 81 million in 2006 .
other charges in 2006 included pretax charges of $ 185 million for estimated environmental remediation costs at sites in new jersey and $ 42 million for legal settlements offset in part by pretax earnings of $ 44 million for insurance recoveries related to the marvin legal settlement and to hurricane rita .
other charges in 2005 included pretax charges of $ 132 million related to the marvin legal settlement net of related insurance recoveries of $ 18 million , $ 61 million for the federal glass class action antitrust legal settlement , $ 34 million of direct costs related to the impact of hurricanes rita and katrina , $ 27 million for an asset impairment charge in our fine chemicals operating segment and $ 19 million for debt refinancing costs .
other earnings increased $ 30 million in 2006 due to higher equity earnings , primarily from our asian fiber glass joint ventures , and higher royalty income .
net income and earnings per share 2013 assuming dilution for 2006 were $ 711 million and $ 4.27 , respectively , compared to $ 596 million and $ 3.49 , respectively , for 2005 .
net income in 2006 included aftertax charges of $ 106 million , or 64 cents a share , for estimated environmental remediation costs at sites in new jersey and louisiana in the third quarter ; $ 26 million , or 15 cents a share , for legal settlements ; $ 23 million , or 14 cents a share for business restructuring ; $ 17 million , or 10 cents a share , to reflect the net increase in the current value of the company 2019s obligation relating to asbestos claims under the ppg settlement arrangement ; and aftertax earnings of $ 24 million , or 14 cents a share for insurance recoveries .
net income in 2005 included aftertax charges of $ 117 million , or 68 cents a share for legal settlements net of insurance ; $ 21 million , or 12 cents a share for direct costs related to the impact of hurricanes katrina and rita ; $ 17 million , or 10 cents a share , related to an asset impairment charge related to our fine chemicals operating segment ; $ 12 million , or 7 cents a share , for debt refinancing cost ; and $ 13 million , or 8 cents a share , to reflect the net increase in the current 2006 ppg annual report and form 10-k 19 4282_txt to be issued options , number of .

Question: Analyse this data from a financial earnings document. what was the change in earnings per share from 2005 to 2006?
Choices:
13.91
0.78
23.51
0.51
-19.73
Correct choice index: 1