$ 43.3 million in 2011 compared to $ 34.1 million in 2010 .
the retail segment represented 13% ( 13 % ) and 15% ( 15 % ) of the company 2019s total net sales in 2011 and 2010 , respectively .
the retail segment 2019s operating income was $ 4.7 billion , $ 3.2 billion , and $ 2.3 billion during 2012 , 2011 , and 2010 respectively .
these year-over-year increases in retail operating income were primarily attributable to higher overall net sales that resulted in significantly higher average revenue per store during the respective years .
gross margin gross margin for 2012 , 2011 and 2010 are as follows ( in millions , except gross margin percentages ) : .

2012
2011
2010
Net sales
$156,508
$108,249
$65,225
Cost of sales
87,846
64,431
39,541
Gross margin
$68,662
$43,818
$25,684
Gross margin percentage
43.9%
40.5%
39.4%

the gross margin percentage in 2012 was 43.9% ( 43.9 % ) , compared to 40.5% ( 40.5 % ) in 2011 .
this year-over-year increase in gross margin was largely driven by lower commodity and other product costs , a higher mix of iphone sales , and improved leverage on fixed costs from higher net sales .
the increase in gross margin was partially offset by the impact of a stronger u.s .
dollar .
the gross margin percentage during the first half of 2012 was 45.9% ( 45.9 % ) compared to 41.4% ( 41.4 % ) during the second half of 2012 .
the primary drivers of higher gross margin in the first half of 2012 compared to the second half are a higher mix of iphone sales and improved leverage on fixed costs from higher net sales .
additionally , gross margin in the second half of 2012 was also affected by the introduction of new products with flat pricing that have higher cost structures and deliver greater value to customers , price reductions on certain existing products , higher transition costs associated with product launches , and continued strengthening of the u.s .
dollar ; partially offset by lower commodity costs .
the gross margin percentage in 2011 was 40.5% ( 40.5 % ) , compared to 39.4% ( 39.4 % ) in 2010 .
this year-over-year increase in gross margin was largely driven by lower commodity and other product costs .
the company expects to experience decreases in its gross margin percentage in future periods , as compared to levels achieved during 2012 , and the company anticipates gross margin of about 36% ( 36 % ) during the first quarter of 2013 .
expected future declines in gross margin are largely due to a higher mix of new and innovative products with flat or reduced pricing that have higher cost structures and deliver greater value to customers and anticipated component cost and other cost increases .
future strengthening of the u.s .
dollar could further negatively impact gross margin .
the foregoing statements regarding the company 2019s expected gross margin percentage in future periods , including the first quarter of 2013 , are forward-looking and could differ from actual results because of several factors including , but not limited to those set forth above in part i , item 1a of this form 10-k under the heading 201crisk factors 201d and those described in this paragraph .
in general , gross margins and margins on individual products will remain under downward pressure due to a variety of factors , including continued industry wide global product pricing pressures , increased competition , compressed product life cycles , product transitions and potential increases in the cost of components , as well as potential increases in the costs of outside manufacturing services and a potential shift in the company 2019s sales mix towards products with lower gross margins .
in response to competitive pressures , the company expects it will continue to take product pricing actions , which would adversely affect gross margins .
gross margins could also be affected by the company 2019s ability to manage product quality and warranty costs effectively and to stimulate demand for certain of its products .
due to the company 2019s significant international operations , financial results can be significantly affected in the short-term by fluctuations in exchange rates. .

Question: Analyse this data from a financial earnings document. what was the increase in gross margin percentage between 2012 compared to 2011?
Choices:
2.8
5.4
-3.4
1778
3.4
Correct choice index: 4