inventory on hand , as well as our future purchase commitments with our suppliers , considering multiple factors , including demand forecasts , product life cycle , current sales levels , pricing strategy and cost trends . if our review indicates that inventories of raw materials , components or finished products have become obsolete or are in excess of anticipated demand or that inventory cost exceeds net realizable value , we may be required to make adjustments that will impact the results of operations . goodwill and non-amortizable intangible assets valuation - we test goodwill and non-amortizable intangible assets for impairment annually or more frequently if events occur that would warrant such review . while the company has the option to perform a qualitative assessment for both goodwill and non-amortizable intangible assets to determine if it is more likely than not that an impairment exists , the company elects to perform the quantitative assessment for our annual impairment analysis . the impairment analysis involves comparing the fair value of each reporting unit or non-amortizable intangible asset to the carrying value . if the carrying value exceeds the fair value , goodwill or a non-amortizable intangible asset is considered impaired . to determine the fair value of goodwill , we primarily use a discounted cash flow model , supported by the market approach using earnings multiples of comparable global and local companies within the tobacco industry . at december 31 , 2018 , the carrying value of our goodwill was $ 7.2 billion , which is related to ten reporting units , each of which consists of a group of markets with similar economic characteristics . the estimated fair value of each of our ten reporting units exceeded the carrying value as of december 31 , 2018 . to determine the fair value of non-amortizable intangible assets , we primarily use a discounted cash flow model applying the relief-from-royalty method . we concluded that the fair value of our non- amortizable intangible assets exceeded the carrying value . these discounted cash flow models include management assumptions relevant for forecasting operating cash flows , which are subject to changes in business conditions , such as volumes and prices , costs to produce , discount rates and estimated capital needs . management considers historical experience and all available information at the time the fair values are estimated , and we believe these assumptions are consistent with the assumptions a hypothetical marketplace participant would use . since the march 28 , 2008 , spin-off from altria group , inc. , we have not recorded a charge to earnings for an impairment of goodwill or non-amortizable intangible assets . marketing costs - we incur certain costs to support our products through programs that include advertising , marketing , consumer engagement and trade promotions . the costs of our advertising and marketing programs are expensed in accordance with u.s . gaap . recognition of the cost related to our consumer engagement and trade promotion programs contain uncertainties due to the judgment required in estimating the potential performance and compliance for each program . for volume-based incentives provided to customers , management continually assesses and estimates , by customer , the likelihood of the customer's achieving the specified targets , and records the reduction of revenue as the sales are made . for other trade promotions , management relies on estimated utilization rates that have been developed from historical experience . changes in the assumptions used in estimating the cost of any individual marketing program would not result in a material change in our financial position , results of operations or operating cash flows . employee benefit plans - as discussed in item 8 , note 13 . benefit plans to our consolidated financial statements , we provide a range of benefits to our employees and retired employees , including pensions , postretirement health care and postemployment benefits ( primarily severance ) . we record annual amounts relating to these plans based on calculations specified by u.s . gaap . these calculations include various actuarial assumptions , such as discount rates , assumed rates of return on plan assets , compensation increases , mortality , turnover rates and health care cost trend rates . we review actuarial assumptions on an annual basis and make modifications to the assumptions based on current rates and trends when it is deemed appropriate to do so . as permitted by u.s . gaap , any effect of the modifications is generally amortized over future periods . we believe that the assumptions utilized in calculating our obligations under these plans are reasonable based upon our historical experience and advice from our actuaries . weighted-average discount rate assumptions for pension and postretirement plan obligations at december 31 , 2018 and 2017 are as follows: . 
||2018|2017|
|Pension plans|1.61%|1.51%|
|Postretirement plans|3.97%|3.79%|
 we anticipate that assumption changes will increase 2019 pre-tax pension and postretirement expense to approximately $ 205 million as compared with approximately $ 160 million in 2018 , excluding amounts related to employee severance and early retirement programs . the anticipated increase is primarily due to higher amortization out of other comprehensive earnings for unrecognized actuarial gains/ losses of $ 14 million , coupled with lower return on assets of $ 16 million , higher interest and service cost of $ 12 million and $ 4 million respectively , partially offset by other movements of $ 1 million . weighted-average expected rate of return and discount rate assumptions have a significant effect on the amount of expense reported for the employee benefit plans . a fifty-basis-point decrease in our discount rate would increase our 2019 pension and postretirement expense by approximately $ 50 million , and a fifty-basis-point increase in our discount rate would decrease our 2019 pension and postretirement .


Question: what is the percentage change in weighted average discount rate for postretirement plans from 2017 to 2018? (in percentage)

Solution:
def solution():
    # Define variables name and value
    postretirement_rate_2018 = 3.97
    postretirement_rate_2017 = 3.79

    # Do math calculation to get the answer
    difference = postretirement_rate_2018 - postretirement_rate_2017
    answer = (difference / postretirement_rate_2017) * 100
    
    return answer
Answer: 4.749340369393145