Are you missing out on car insurance discounts?

If you haven't asked your car insurance provider for a discount, you're not alone.

Only 16 percent of Americans have asked about common discounts, such as lower rates for people who drive fewer than 5,000 miles per year, according to a new survey from insuranceQuotes.com. The survey looked at a number of discounts that must be self-reported, which ends up being a hitch for many consumers, especially if they aren't aware of them.

"I can only assume people aren't taking advantage of them because they don't know about it," Laura Adams, senior analyst at insuranceQuotes.com, told CBS MoneyWatch. "There is an education gap there. They don't know these discounts exist, and you have to be proactive to ask for them."

Consumers should call their insurers every year to check if they qualify for certain discounts, given that life events, such as getting married or moving closer to a workplace, can change one's rate. The insurance discounts include those for low-mileage drivers, married drivers, occupational discounts, good student discounts and defensive-driver discounts.

Someone who drives less than 5,000 miles each year pays an average of 8 percent less than someone who drives 15,000 miles annually, for instance. Drivers in California save the most on this discount, paying 25 percent less than higher-mileage drivers.

Only 13 percent of Americans have told their insurance carriers that they got married, something that can save on insurance. A married 25-year-old pays 7 percent less than a single American, for instance.

Good students can also get lower rates, something that can help families of teenagers or college students, who tend to pay higher premiums. Typically, these drivers have to prove they're earning at least a B average in their classes, Adams said.

"The good student discount is one that really goes missed," Adams said. "I don't think I've ever talked to anyone who used that. That can really help parents of teen drivers, because they are some of the most expensive drivers on the road because statistically they get into more accidents."

Certain professions also qualify for lower rates, such as serving in the armed forces or working as a teacher, nurse or accountant. Only about 8 percent of Americans have asked for occupational discounts, the survey found.

When getting on the phone with your insurer, Adams recommends that consumers ask, "What discounts do you offer? What else might I be qualified for." She added, "Try to get the insurance company to run through what they are really offering so you can find out if you fit into any of those."