Adding a teenage driver to a married couple's car insurance policy leads to a 79% higher average annual premium, according to a new insuranceQuotes.com report. Teenage males (+92%) are much more expensive to insure than teenage females (+67%). The good news is that the premium increases decline each year, from 96% for 16-year-olds to 58% for 19-year-olds.

The most expensive state to insure a teenage driver is New Hampshire, where the average premium spikes by 111%. The Granite State is one of seven states where premiums more than double after adding a teen driver to the policy. The others are Rhode Island (+107%), Maine (+107%), Wyoming (+106%), Connecticut (+102%), Illinois (+101%) and Oregon (+101%).

Hawaii is the only state that prohibits age, gender and length of driving experience from affecting car insurance costs. As a result, teen drivers only cost 17% more to insure in Hawaii, the lowest increase in the nation by far. New York State (+53%) has the second-lowest increase, followed by Michigan (+57%), Montana (+61%) and New Mexico (+62%).

The cost to insure a teenage driver fell over the past year. In 2013, the average annual increase was 85% (98% for males and 73% for females).

"A great strategy for lowering car insurance costs is to sign up for pay-as-you-drive car insurance," said Laura Adams, senior analyst, insuranceQuotes.com. "These programs allow companies to track your driving habits and can lead to significant discounts, especially if you're a safe driver who doesn't rack up too many miles. Teens who excel in the classroom should also take advantage of good student discounts."