Seattle City Light 2016 ANNUAL REPORT | Audited Financial Statements 61 THE CITY OF SEATTLE—CITY LIGHT DEPARTMENT NOTES TO FINANCIAL STATEMENTS AS OF AND FOR THE YEARS ENDED DECEMBER 31, 2016 AND 2015 - 61 - Actuarial data and assumptions Valuation date January 1, 2014 Actuarial cost method Entry age normal Amortization method Level dollar Initial amortization period 30 years, open Discount rate 3.48% Health care cost trend rates—medical: Aetna plans: 8.0%, decreasing by 0.5% each year for 2 years with varying rate changes thereafter. Group Health plans: 7.5%, decreasing by 0.5% each year for 3 years with varying rate changes thereafter. Participation 40% of Active Employees who retire participate Mortality General Service Actives and Retirees based on RP-2000 Table and RP- 2000 Combined Healthy, respectively, with ages set back six years for male and female actives; set back two years for male and female retirees. Rates are generational for both males and females using Projection Scale AA. Marital status 45% of members electing coverage: married or have a registered domestic partner. Male spouses two years older than their female spouses. Morbidity factors Aetna Traditional & Aetna Preventive Per-capita claim costs for the two Aetna plans were developed based on a blending of the following with equal weights (25% each): self-funding premium equivalent rates provided by City of Seattle, Aon Hewitt’s internal manual rate, retiree claim experience specific to each plan from 1/1/2012 to 8/31/2014, and active claim experience specific to the Aetna plans from 1/1/2012 to 8/31/2014. For the Aetna plans, because the retirees' spouses pay a lower premium for health care coverage than retirees, the net cost to the City for the spouse coverage is greater than for a retiree of the same age and gender. The morbidity factors were adjusted to reflect this discrepancy. Group Health Standard and Deductible Plans Per-capita claim costs for the two Group Health plans were developed based on a blending of the following with equal weights (33.3% each): self-funding premium equivalent rates provided by City of Seattle, Aon Hewitt’s internal manual rate, and retiree claim experience specific to each plan from 1/1/2012 to 8/31/2014. Other considerations Active employees with current spouse and/or dependent coverage elect same plan and coverage. After retirement, it is assumed that children will have aged off of coverage and will have $0 liability.