pre_text: The Company sponsors a defined benefit plan, the Woolworths Group Superannuation Plan (WGSP or the Plan), that provides superannuation benefits for employees upon retirement. The defined benefit plan is closed to new members. The assets of the WGSP are held in a sub-plan within AMP SignatureSuper that is legally separated from the Group. The WGSP invests entirely in pooled unit trust products where prices are quoted on a daily basis. The WGSP consists of members with defined benefit entitlements and defined contribution benefits. The plan also pays allocated pensions to a small number of pensioners. The following disclosures relate only to the Group’s obligation in respect of defined benefit entitlements. The Group contributes to the WGSP at rates as set out in the Trust Deed and Rules and the Participation Deed between the Group and AMP Superannuation Limited. Members contribute to the WGSP at rates dependent upon their membership category. The plan provides lump sum defined benefits that are defined by salary and period of membership. An actuarial valuation was carried out at both reporting dates by Mr Nicholas Wilkinson, FIAA, Willis Towers Watson. The principal actuarial assumptions used for the purpose of the valuation are as follows:
table: 2019 2018
table: % %
table: Discount rate 2.9 3.8
table: Expected rate of salary increase 2.5 2.5
table: Rate of price inflation 2.0 2.0
question: Analyse this data from a financial earnings document. What is the change in expected rate of salary increase between 2018 and 2019?