How to write a Dax measure using the date table with mutable IF conditions

Dear All,

I need help in writing a Dax measure using the date table with mutable IF conditions as below:

I need two measures  :

1- (total days btween the date that I'll select in the silcer and the employee Hire Date  + the Extra days / 365 ) now we will have the years of employment for each in a measure or a coulmn, now in other measure or the same one if the years >=18 I need to return 100% if it's >=15 return 75% if >=12 return 50% if >=9 return 25% other return 0

if the employee hire date is 01-01-2010 and the slicer date is 01-01-2023 he will have 13 years then he will be 50%, if the slicer date is 01-01-2027 he will have 17 Years then he will be 75%

2- the other measure is the easy one if we complete the above, it will take the years of employment * the Salary * the above mesure % 100% or 75% or 50% or 25%.

thank you for your help in advance 

please find the below data to be used: