Sister,birthfamily spokane? 1976-1977?

I am searching for a sister that would not know that I exist. She was born in either 1976 or 1977. Our birthmother/father put her up for adoption, when she was 18 and he was 21. I have a vague information sheet on a description of them and what they were aspiring to be. I was born in Spokane in Feb. 1979. Sacred Heart Memorial Hospital. They also put me up for adoption. I am looking for anyone!