We present a measurement of the muon charge asymmetry from the decay of the W boson via W→μν using 7.3  fb-1 of integrated luminosity collected with the D0 detector at the Fermilab Tevatron Collider at √s=1.96  TeV. The muon charge asymmetry is presented in two kinematic regions in muon transverse momentum and event missing transverse energy: (pTμ>25  GeV, E̸T>25  GeV) and (pTμ>35  GeV, E̸T>35  GeV). The measured asymmetries are compared with theory predictions made using three parton distribution function sets. The data at pTμ>35  GeV, E̸T>35  GeV, and larger values of |ημ| favor an increased d(x)/u(x) ratio at higher values of x than is predicted.