In general, states impose a use tax out of two concerns: (1) that local merchants will lose business if taxpayers purchase goods out-of-state to avoid sales tax liability; (2) that the state will lose tax revenue if taxpayers purchase goods out-of-state. JEROME R. HELLERSTEIN & WALTER HELLERSTEIN, 2 STATE TAXATION 16.01[2] (3d ed. 2000). "To deal with this potential loss of business and revenue, states enacted 'complementary' or 'compensating' use taxes on the use of goods purchased outside of the state and brought into the state for use." Id. A use tax is functionally equivalent to a sales tax and is "typically levied upon the use, storage, or other consumption in the state of tangible personal property that has not been subjected to a sales tax." Id. Indiana's use tax (a) . . . is imposed on the storage, use, or consumption of tangible personal property in Indiana if the property was acquired in a retail transaction, regardless of the location of that transaction or of the retail merchant making that transaction. (b) the use tax is also imposed on the storage, use, or consumption of a vehicle, an aircraft, or a watercraft, if the vehicle, aircraft, or watercraft: (1) is acquired in a transaction that is an isolated or occasional sale; and (2) is required to be titled, licensed, or registered by this state for use in Indiana. IND. CODE 6-2.5-3-2 (1998). the rate of Indiana's use tax is the same as Indiana's sales tax rate. IND. CODE 6-2.5-3-3 (1998). See also IND. CODE 6-2.5-2-2(a) (1998) (imposing a 5% sales tax rate on purchases of $ 0.90 or more). Accordingly, Indiana's use tax complements Indiana's sales tax to ensure that non-exempt retail transactions (particularly out-of-state retail transactions) that escape sales tax liability are nevertheless taxed. See USAir, Inc. v. Indiana Dep't of State Revenue, 623 N.E.2d 466, 468-69 (Ind. Tax Ct. 1993). Indiana Code Section 6-2.5-3-6(d) exempts a taxpayer from Indiana's use tax if he proves that he has already paid "the use tax or state gross retail tax" on the purchase of his vehicle. I.C. 6-2.5-3-6(d). The statute, however, does not expressly indicate whether the taxes mentioned are any state's taxes or just Indiana's. See id. On the other hand, Indiana Code Section 6-2.5-3-5(b) denies any use tax credit for the payment of another state's sales or use tax when a taxpayer purchases a vehicle out-of-state but is required to title the vehicle for use in Indiana. I.C. 6-2.5-3-5(b); Williams v. Indiana Dep't of State Revenue, 742 N.E.2d 562, 564 (Ind. Tax Ct. 2001).