| Share | Phrase |
|---|
| 34.91% | principal [importance] object |
| 8.83% | principal [importance] part |
| 6.88% | principal [importance] portion |
| 6.21% | principal [importance] fuel |
| 5.29% | principal [importance] component |
| 4.92% | principal [importance] feature |
| 2.71% | principal [importance] passage |
| 2.30% | principal [importance] axis |
| 2.07% | principal [importance] element |
| 1.85% | principal [importance] valve |
| 1.44% | principal [importance] advantage |
| 1.44% | principal [importance] catalyst |
| 1.29% | principal [importance] difference |
| 1.17% | principal [importance] injection |
| 1.08% | principal [importance] illustration |
| 1.00% | principal [importance] comparator |
| 0.92% | compression [attribute] principal |
| 0.85% | principal [importance] aspect |
| 0.78% | principal [importance] objective |
| 0.73% | principal [importance] member |
| 0.73% | principal [importance] system |
| 0.71% | principal [importance] direction |
| 0.69% | principal [importance] compression |
| 0.62% | principal [importance] two-cycle |
| 0.62% | two-cycle [attribute] principal |
| 0.61% | principal [importance] area |
| 0.61% | principal [importance] problem |
| 0.55% | principal [importance] surface |
| 0.54% | principal [importance] consideration |
| 0.53% | principal [importance] body |
| 0.51% | principal [importance] purpose |
| 0.51% | principal [importance] zone |
| 0.47% | principal [importance] mixture |
| 0.46% | principal [importance] particle |
| 0.43% | principal [importance] function |
| 0.41% | principal [importance] range |
| 0.40% | principal [importance] throttle |
| 0.37% | principal [importance] disadvantage |
| 0.37% | principal [importance] supply |
| 0.36% | principal [importance] ax |
| 0.36% | principal [importance] pollutant |
| 0.36% | principal [importance] view |
| 0.35% | principal [importance] embodiment |
| 0.34% | principal [importance] source |
| 0.33% | principal [importance] line |
| 0.29% | principal [importance] unit |
| 0.29% | principal [importance] means |
| 0.25% | principal [importance] mechanism |