relatively stable stage meaning in English

相对稳定阶段

The first period is from 1958 to 1959 , which is its initial stage ; the second period is from 1960 to 1961 , which is its continuous adjustment stage ; the third period is from 1962 to 1965 , which is its relatively stable stage ; the fourth period is from 1966 to 1977 , which is its undulate stage ; the fifth period is from 1978 to 1985 , which is its gradual abolishment stage
一是1958年至1959年，为其初期兴办阶段；二是1960年至1961年，为其继续调整阶段；三是1962年至1965年，为其发展相对稳定阶段；四是1966年至1977年，为其发展较为波动阶段；五是1978年至1985年，为其逐步取消阶段。