设函数\(f(x)=\)\( \dfrac{1}{2}\)\(+\log \)\({\,\!}_{2} \dfrac{x}{1-x}\)，定义\(S\)\({\,\!}_{n}\)\(=f\)\(\left( \left. \dfrac{1}{n} \right. \right)\)\(+f\)\(\left( \left. \dfrac{2}{n} \right. \right)\)\(+…+f\)\(\left( \left. \dfrac{n-1}{n} \right. \right)\)，其中\(n∈N\)\({\,\!}^{*}\)，且\(n\geqslant 2\)，则\(S\)\({\,\!}_{n}\)\(=\)________．