It depends on what type of electric current you are talking of.
In case of AC current,the inductance decreases from center towards the surface of the wire. As current flows through the path of least resistance, it flows through the surface of the wire which provides path of least Reactance. This phenomena where current flows through the surface due to least reactance is known as "Skin effect".
While in case of DC current the inductance part is missing as there is no change in flux with respect to time. So the resistance is same through out the conductor. Hence DC current flows through out the wire cross-section.
If,you visit any power GRID you’ll see the bus bars are hollow. This is because current flows through the outer surface so bars are kept hollow to carry same current, avoiding material wastage.