 The pattern of electoral hegemony seemed set to continue into the 1960s.At the 1966 General Election Welsh Labour's share topped 60%, gaining it all but 4 of Wales's 36 Parliamentary constituencies.Within three months, however, Gwynfor Evans sensationally captured Carmarthen for Plaid Cymru at a by-election, and the Nationalists came within a whisker of victory at the 1967 Rhondda West and 1968 Caerphilly by-elections, achieving huge swings against Labour of 30% and 40% respectively.