Ranking: 27

Percentage score: 69.1%

Ranking: 26

Percentage score: 72.5%

Ranking: 25

Percentage score: 74.5%

Ranking: 24

Percentage score: 75.0%

Ranking: 23

Percentage score: 75.4%

Ranking: 22

Percentage score: 75.6%

Ranking: 21

Percentage score: 75.8%

Ranking: 20

Percentage score: 76.2%

Ranking: 18

Percentage score: 77.1%

Apparently the diamond was an integral part of the design of the early cars - which was fitted around an air hole in the bonnet.