At the point of German-Soviet conflict, the US had about six times the steel production of the USSR, six times the iron production, eight times the oil production, and three to four times the coal production. It definitely wouldn't be surprising if US steel was a large share of Soviet figures.

The scale of resources delivered to prop up the Soviets was extraordinary, including what the British sent them.

In just 3 1/2 years the British sent them[1]:

3,000+ Hurricanes aircraft, 4,000+ other aircraft, 27 naval vessels, 5,218 tanks, 5,000+ anti-tank guns, 4,020 ambulances and trucks, 323 machinery trucks, 1,212 Universal Carriers and Loyd Carriers, 1,721 motorcycles, £1.15bn worth of aircraft engines, 1,474 radar sets, 4,338 radio sets, 600 naval radar and sonar sets

And the US sent them:

427,284 trucks, 13,303 combat vehicles, 35,170 motorcycles, 2,328 ordnance service vehicles, 2,670,371 tons of petroleum products (gasoline and oil) or 57.8 percent of the High-octane aviation fuel,[32] 4,478,116 tons of foodstuffs (canned meats, sugar, flour, salt, etc.), 1,911 steam locomotives, 66 Diesel locomotives, 9,920 flat cars, 1,000 dump cars, 120 tank cars, and 35 heavy machinery cars. Provided ordnance goods (ammunition, artillery shells, mines, assorted explosives) amounted to 53 percent of total domestic production

Beyond Russia also notes:

"The USSR received a total of 44,000 American jeeps, 375,883 cargo trucks, 8,071 tractors and 12,700 tanks. Additionally, 1,541,590 blankets, 331,066 liters of alcohol, 15,417,000 pairs of army boots, 106,893 tons of cotton, 2,670,000 tons of petroleum products and 4,478,000 tons of food supplies"

The notion of sending a country 375,000 trucks and 1,900 locomotives in just three years, is incredible to think of today.

[1] https://en.wikipedia.org/wiki/Lend-Lease