From Finland’s War of Choice: The Troubled German-Finnish Coalition in World War II, by Henrik Lunde (Casemate, 2011), Kindle Loc. 1640-47, 1654-58:
What arrived in the Soviet Union via Murmansk was only part of the immense flow of aid from the Western democracies. Aid via the Persian Gulf began arriving in 1942 but the flow was small until 1943 when the railway system between Basra and the Caspian Sea area had been expanded sufficiently to accommodate the traffic. The supplies and equipment arriving by this route eventually amounted to about 25 percent of all aid to the Soviet Union.
The largest flow, accounting for about half the aid, came across the Pacific to Soviet eastern ports. The possibility that this route would be disrupted by the Japanese was taken into account and Stalin warned Japan not to interfere. Thus approximately 25 percent of the aid came via Murmansk and Archangel. The total tonnage shipped via the northern route was 3,964,231 out of a total of 16,366,747.
Between March 1941 and December 1945, the United States of America contributed to Russia: 14,795 aircraft; 7,537 tanks; 51,503 jeeps; 35,170 motor bicycles; 8,700 tractors; 375,883 trucks and lorries; 8,218 anti-aircraft guns; 131,633 submachine guns; 345,735 tons of explosives; 1,981 locomotives; 11,155 railway wagons and trucks; 540,000 tons of steel rails; in excess of 1 million miles of telephone cable; food shipments to the value of $1,312 million; 2,670,000 tons of petrol; 842,000 tons of chemicals; 3,786,000 tyres; 49,000 tons of leather; and 15 million pairs of boots. The total value of the above is said to be $11,260,343,603.