z i m m e r h o l d i n g s , i n c . a n d s u b s i d i a r i e s 2 0 0 4 f o r m 1 0 - k for the same 2003 period . amortization expense increased togross profit $ 39.1 million , or 1.3 percent of sales , during the year ended gross profit as a percentage of net sales was december 31 , 2004 compared to $ 10.9 million , or less than 73.8 percent in 2004 , compared to 72.8 percent in 2003 and 1 percent of sales , during the year ended december 31 , 2003 . 68.1 percent for the three month period ended december 31 , the increase was primarily due to amortization expense 2003 ( the first quarter of combined zimmer and centerpulse related to centerpulse and implex finite lived intangible operations ) . the following table reconciles the gross margin assets . in addition , during 2004 the company continued to for the year ended december 31 , 2004 and for the three introduce or expand strategic programs and activities . in month period ended december 31 , 2003 . 2004 , the zimmer institute and its satellite locations were well utilized with over 1400 surgeons trained , compared tothree month period ended december 31 , 2003 500 surgeons trained in 2003 . these surgeon training costsgross margin 68.1% ( 68.1 % ) are recognized in sg&a . the company also recognizedinventory step-up charge 4.1 approximately $ 5 million of sarbanes-oxley complianceincreased average selling prices 1.8 expenses , including consultant fees and increased audit fees.operating segment and product category mix 0.2 these increases were partially offset by expense synergiesother ( 0.4 ) realized from the centerpulse acquisition and controlled .

Table:
three month period ended december 31 2003 gross margin | 68.1% ( 68.1 % )
inventory step-up charge | 4.1
increased average selling prices | 1.8
operating segment and product category mix | 0.2
other | -0.4 ( 0.4 )
year ended december 31 2004 gross margin | 73.8% ( 73.8 % )
spending .
the company has begun to realize synergies from the centerpulse acquisition and expects to pursue additionaldecreased centerpulse and implex inventory step-up synergy opportunities .
the company estimates that over thecharges as a percentage of net sales during 2004 next two years it will be able to reduce annual sg&a as a ( $ 59.4 million , or 2.0 percent of net sales ) compared to the percentage of net sales to 38.9 percent or lower , representingthree month period ended december 31 , 2003 ( $ 42.7 million , a 200 basis point improvement over the fourth quarter ofor 6.1 percent of net sales ) and increases in average selling 2003 ( the first quarter of combined zimmer and centerpulseprices were the primary contributors to improved gross operations ) .margins .
in addition , operating segment mix and product acquisition and integration expenses related to thecategory mix both had a positive impact on gross margins acquisitions of centerpulse and implex were $ 81.1 milliondue to higher sales growth in the more profitable americas compared to $ 79.6 million for the same 2003 period andsegment compared to europe and asia pacific , higher sales included $ 24.4 million of sales agent and lease contractgrowth of reconstructive implants and the continued shift to termination expenses , $ 24.2 million of integration consultingpremium products .
offsetting these favorable impacts were a expenses , $ 9.4 million of employee severance and retentionvariety of other items , including increased royalty expenses expenses , $ 7.8 million of professional fees , $ 5.2 million ofand higher losses on foreign exchange contracts included in personnel expenses and travel for full-time integration teamcost of products sold , partially offset by reduced members , $ 4.3 million of costs related to integrating themanufacturing costs due to automation , vertical integration company 2019s information technology systems , $ 2.9 million ofand process improvements .
costs related to relocation of facilities , and $ 2.9 million of operating expenses other miscellaneous acquisition and integration expenses .
r&d as a percentage of net sales was 5.6 percent for operating profit , income taxes and net earnings years ended december 31 , 2004 and 2003 .
r&d increased to operating profit for the year ended december 31 , 2004$ 166.7 million from $ 105.8 million reflecting a full year of increased 69 percent to $ 763.2 million from $ 450.7 million incenterpulse research and development expenses and the comparable 2003 period .
operating profit growth wasincreased spending on active projects focused on areas of driven by zimmer standalone sales growth , operating profitstrategic significance .
the company 2019s pipeline includes 146 contributed by centerpulse , effectively controlled operatingprojects with a total investment equal to or greater than expenses and the absence of in-process research and$ 1 million .
of the 146 projects , approximately two-thirds development expense in 2004 compared to $ 11.2 million ininvolve new platforms , mis or other technologies .
for 2003 .
these favorable items were partially offset byexample , the company 2019s orthobiological research group in centerpulse and implex inventory step-up of $ 59.4 million inaustin , texas is developing innovative solutions for hip 2004 compared to $ 42.7 million in 2003 and intangible assetfracture and cartilage regeneration .
during 2004 , the amortization of $ 39.1 million in 2004 versus $ 10.9 million incompany delivered more than 40 major development projects 2003.to market .
the company has strategically targeted r&d the effective tax rate on earnings before income taxesspending to be at the high end of what management believes minority interest and cumulative effect of change into be an average of 4-6 percent for the industry .
the accounting principle decreased to 25.9 percent for the yearcompany expects over the next few years to invest in ended december 31 , 2004 from 33.6 percent for the sameresearch and development at approximately 5.5 percent to period in 2003 .
a major component of the decrease6 percent of sales .
( 4.7 percent , or $ 34.5 million ) was the result of revaluingsg&a as a percentage of net sales was 39.9 percent for deferred taxes of acquired centerpulse operations due to athe year ended december 31 , 2004 compared to 38.8 percent reduction in the ongoing swiss tax rate .
the major reasons .

Question: what was the total change in gross margins between december 31 , 2003 and december 312004?
Answer: 5.7%
Calculation: divide(73.8, 68.1)