P-31-NMR measurements were performed in the iron pnictides BaFe2(As1-xPx)(2) for 0.07 <= x <= 0.64 in order to investigate evolution of electronic state with isovalent substitution. In general, the spin part of the Knight shift K-spin and (T1T)(-1/2) are proportional to the quasiparticle density of states at the Fermi level N(E-F) at high temperature where the Korringa relation holds. We found that K-spin and (T1T)-(1/2) are almost unaffected by the P-substitution, indicating that N (E-F) is nearly constant. These results are quantitatively consistent with our band calculation. We claim that the slight changes of N(E-F) by P-substitution in BaFe2(As1-xPx)(2) is not enough to explain the T-c variation ranging from 30 K to 0 K, and thus suggest that antiferromagnetic correlations related to the quantum critical character are essential for the high T-c superconductivity.