Of the five main political parties in Northern Ireland, four (the Ulster Unionist Party, the Democratic Unionist Party, the Social Democratic and Labour Party and Sinn Féin) all have relatively strong support bases and routinely poll similar results. Other parties such as the Alliance, Progressive Unionist Party, Unionist Party of Northern Ireland, Conservatives and the Workers' Party have at times polled significantly, as have independent candidates, with the result that many elections have been won on comparatively low shares of the vote. The elections to the various assemblies have often seen the seats for the constituency heavily split – in 1998 no party won more than one Assembly seat.