Female sibling born 1945 search

Hello, Looking for my birth sister who was adopted at birth or shortly after in Seattle. Date of birth 4/14/1945 at Cabrini Hospital. At time of birth her given name was Barbara. May have been taken to Oregon for adoption. Mother and father were not married and both from Washington State. Biological mother lived in King County and possibly Kitsap County as well. Any information would be appreciated.