1. Make $100 from selling oil.
2. Use the money to buy other local services.
There, now your GDP is just 50% oil.
There, now your GDP is just 50% oil.
[1]: https://www.regjeringen.no/no/tema/okonomi-og-budsjett/norsk...
For sure, it's a huge part of Norway and shouldn't be overlooked, but it's specious to compare it directly to a country like Saudi Arabia.