I've had the same question, the answer is longitude.
Petroleum products. So oil and natural gas etc.
Jewelry and precious stones come in second.
I think is 152 million km
When a product is elastic, a change in price quickly results in a change in the quantity demanded. When a good is inelastic, there is little change in the quantity of demand even with the change of the good's price. ... If the market price goes up, firms are likely to increase the number of goods they are willing to sell.
D. Plateau
I'm sure there are no more.
Hope that helps! c: