Table:
text: Israeli National Badminton Championships
Past winners
Past winners
Year_ Men_s_singles Women_s_singles Men_s_doubles Women_s_doubles Mixed_doubles
1977 Victor Yusim Chaya Grunstein Victor Yusim Michael Schneidman Vivian Meirowitz Carol Silman Michael Schneidman Dianne Levi
1978 Nissim Duk Chaya Grunstein Victor Yusim Michael Schneidman Carol Silman Prina Ben Shushan Michael Rappaport Gila Rappaport
1979 Yitzhak Serrouya Eva Unglick Victor Yusim Michael Schneidman no competition Michael Rappaport Eva Unglick
1980 Yitzhak Serrouya Eva Unglick Nissim Duk Yitzhak Serrouya Eva Unglick Irit Ben Shushan Michael Rappaport Eva Unglick
1981 Nissim Duk Eva Unglick Victor Yusim Michael Rappaport Eva Unglick Irit Ben Shushan Michael Rappaport Eva Unglick

Question: What was the winner among the Israel National Badminton Championships before 1979 when Carol Silman Prina Ben Shushan won the women's doubles?