Read the following texts and table with financial data from an S&P 500 earnings report carefully.Based on the question-answer history (if provided), answer the last question. The answer may require mathematical calculation based on the data provided.


13 . pension and other postretirement benefit plans the company has defined benefit pension plans covering eligible employees in the united states and in certain of its international subsidiaries . as a result of plan design changes approved in 2011 , beginning on january 1 , 2013 , active participants in merck 2019s primary u.s . defined benefit pension plans are accruing pension benefits using new cash balance formulas based on age , service , pay and interest . however , during a transition period from january 1 , 2013 through december 31 , 2019 , participants will earn the greater of the benefit as calculated under the employee 2019s legacy final average pay formula or their new cash balance formula . for all years of service after december 31 , 2019 , participants will earn future benefits under only the cash balance formula . in addition , the company provides medical benefits , principally to its eligible u.s . retirees and their dependents , through its other postretirement benefit plans . the company uses december 31 as the year-end measurement date for all of its pension plans and other postretirement benefit plans . net periodic benefit cost the net periodic benefit cost for pension and other postretirement benefit plans consisted of the following components: . <table class='wikitable'><tr><td>1</td><td>years ended december 31</td><td>pension benefits 2013</td><td>pension benefits 2012</td><td>pension benefits 2011</td><td>pension benefits 2013</td><td>pension benefits 2012</td><td>2011</td></tr><tr><td>2</td><td>service cost</td><td>$ 682</td><td>$ 555</td><td>$ 619</td><td>$ 102</td><td>$ 82</td><td>$ 110</td></tr><tr><td>3</td><td>interest cost</td><td>665</td><td>661</td><td>718</td><td>107</td><td>121</td><td>141</td></tr><tr><td>4</td><td>expected return on plan assets</td><td>-1097 ( 1097 )</td><td>-970 ( 970 )</td><td>-972 ( 972 )</td><td>-126 ( 126 )</td><td>-136 ( 136 )</td><td>-142 ( 142 )</td></tr><tr><td>5</td><td>net amortization</td><td>336</td><td>185</td><td>201</td><td>-50 ( 50 )</td><td>-35 ( 35 )</td><td>-17 ( 17 )</td></tr><tr><td>6</td><td>termination benefits</td><td>58</td><td>27</td><td>59</td><td>50</td><td>18</td><td>29</td></tr><tr><td>7</td><td>curtailments</td><td>-23 ( 23 )</td><td>-10 ( 10 )</td><td>-86 ( 86 )</td><td>-11 ( 11 )</td><td>-7 ( 7 )</td><td>1</td></tr><tr><td>8</td><td>settlements</td><td>23</td><td>18</td><td>4</td><td>2014</td><td>2014</td><td>2014</td></tr><tr><td>9</td><td>net periodic benefit cost</td><td>$ 644</td><td>$ 466</td><td>$ 543</td><td>$ 72</td><td>$ 43</td><td>$ 122</td></tr></table> the increase in net periodic benefit cost for pension and other postretirement benefit plans in 2013 as compared with 2012 is largely attributable to a change in the discount rate . the net periodic benefit cost attributable to u.s . pension plans included in the above table was $ 348 million in 2013 , $ 268 million in 2012 and $ 406 million in in connection with restructuring actions ( see note 3 ) , termination charges were recorded in 2013 , 2012 and 2011 on pension and other postretirement benefit plans related to expanded eligibility for certain employees exiting merck . also , in connection with these restructuring activities , curtailments were recorded in 2013 , 2012 and 2011 on pension and other postretirement benefit plans . in addition , settlements were recorded in 2013 , 2012 and 2011 on certain domestic and international pension plans . table of contents .
Question: what was the service cost in 2013?
Answer: 682.0
Question: and what was it in 2012?
Answer: 555.0
Question: how much, then, did the 2013 amount represent in relation to this 2012 one?
Answer: 1.22883
Question: and what is this value excluding the part equivalent to the 2012 amount?
Answer: 0.22883
Question: and between those two years, what was the variation in the net amortization?

151.0