Why did western nations become interested in saudi arabia during the twentieth century?

saudi arabia abandoned islamic law.
the nation set up european-style courts.
oil was discovered on the arabian peninsula.

Oil was discovered on the Arabian peninsula.

Explanation:

The proven oil reserves in Saudi Arabia are the second largest in the world, just behind Venezuela's reserves. They are estimated at 267 billion barrels (42 × 10 ^ 9 m3) including 2.5 billion barrels in the Saudi-Kuwaiti Neutral Zone. This is about one fifth of the total of the world's conventional oil reserves. Although Saudi Arabia has around 100 oil and gas fields, more than half of its oil reserves are found in only eight giant oil fields, including the field of Ghawar Field, the largest oil field in the world with an estimated of 70 billion barrels (11 × 10 ^ 9 m3) of the remaining reserves. Saudi Arabia maintains the world's largest crude production capacity, estimated at around 11 million barrels per day (1.7 × 10 ^ 6 m3 / d) by mid-2008 and has announced plans to increase this capacity to 12, 5 million barrels per day (2.0 × 10 ^ 6 m3 / d) in 2009.

war never

hello there!

the graphics that you have attached within the question, indicates that few people in bolivia work in industry according to its labor force.

however, the graphic that is on the right side of the picture shows the gdp sector in bolivia. this gross domestic product is a macroeconomic magnitude   that shows the monetary value of all finished goods and services within a country's borders in a specific time period. in this case, the graphic is showing the monetary value in each sector -agriculture, industry and services- of bolivia in 2012.

so, although the first graphic located at the left side indicates that not so many people work in industry, this is the second most important sector according to the gdp metrics because of the monetary value that impacts on its country. it does not need to be the most valuable one. if it makes an impact on the country's economy, it will be definitely crucial to it.