An experimental analysis of the turbulent boundary layer subject to wall-normal suction is carried out on a 6.4 m long perforated plate by means of hot-wire anemometry. For this type of flow the scaling of the mean velocity and of the other statistical quantities remains an open question and the amount of experimental data available, especially regarding the fluctuating velocity components, is scarce. The longer streamwise length of the present experimental apparatus compared to the one used in the previous studies allows us to better investigate the development of the boundary layer: it is shown that a turbulent asymptotic state with a constant boundary-layer thickness, analogously to what happens for the laminar state, can be closely approached experimentally and that its mean velocity profile exhibit a clear logarithmic region.