Incremental

[,ɪnkrɪ'mentəl] or [ɪnkrə'məntl]

(adj.) increasing gradually by regular degrees or additions; 'lecturers enjoy...steady incremental growth in salary' .

Typed by Julie--From WordNet

(a.) Pertaining to, or resulting from, the process of growth; as, the incremental lines in the dentine of teeth.

Typed by Frank