How did petrodollars change the world economy from the 1970s?

They increased the availability of loans for developing states.

It's possible that the Birdman practices had been going on during the reign of the statue cult; however, it eventually took over as the predominate religion on the island and was still in practice up untill 1866-67. High on the rim of the crater known as Rano Kau was the ceremonial village of Orongo.