I don't know about the 70 or whatever percentage, but when the L405 launched, during the initial months the majority of them were exported. Then, Land Rover dealers started to demand ridiculous things from customers with no previous purchase history (like, bank statement, or copy of registration in states where the dealer has no business with the registration, selling with financing only, all-cash not accepted, signed paper to not re-sell the car without Land Rover's OK, etc) that were all cooked up as ideas to eliminate straw-men purchases that went straight to China and Russia. Many people made money on '13s driving them for 5-10-15k miles, and then selling it to exporters for more than the original MSRP. You literally had people walk up to you in parking lots, offering cash for the vehicle right there and then. It happened to me, not once.
I had to sign a paper even for my '14 that if I sell it with less than 25k miles on it, I had to offer it to the dealership first.
All these were done because Land Rover effectively punished dealers for the grey export. Since they had no tools to stop this grey-export (since it's 100% lawful), they revoked allocation from dealers that had a certain level of re-export rates, things like that. And this hurt dealers, because initially they had 2-3 cars a month, at most. And when a new customer came in, they had to basically play police/IRS vetting the potential buyer - which of course came across like being complete dorks.
And in the meantime, the lots were literally empty.
So yea, it was a really big deal in the first year.
None of these stopped the exports. The true end of it was China's tax increase on cars with larger than 3L engines. Remember, when launched, a supercharged '13 cost exactly four times as much in China as it did here in the States, and the vast majority of that difference was Land Rover's and its dealers' profit there. Once the taxes were jacked up, they had to let the dream profit go, and it wasn't worth grey exporting that much.
FWIW there was no Velar then. The Evoque was just launching, the Sport was still on its first generation, the LR4 was nothing new really, nobody wanted the Freelander - it was all about the brand new full size, re-export, and shortage.
I had one of the first '13 L405 in New England, after an 8 months wait. That launch and model year was CRAZY.