Researchers have assessed the fit of safety belts on 72 booster seats and found that more models made the grade than last year, but poor performers still surfaced, according to the Insurance Institute for Highway Safety.

Of the boosters reviewed, 21 were given a "best bet" rating and seven earned a "good bet" rating, while eight failed to be recommended at all. This compared with last year, when nine seats out of 60 earned a "best bet" rating.

"Now more than ever manufacturers are paying attention to belt fit, and it's showing up in our ratings," said Anne McCartt, institute senior vice president for research.

Rounding out the list of boosters evaluated this year were 36 that fell in the middle because they don't consistently fit belts well on most kids in most vehicles. Most in this category are backless boosters with good lap-belt scores but poor shoulder-belt scores.

"Unlike the top performers, consumers can't assume boosters in the in-between group will work in every family vehicle. Some may be fine, but parents still need to try them out to see if the lap and shoulder belts fit their kids correctly," McCartt said.

The Institute said that children ages 4 to 8 who ride in boosters are 45 percent less likely to be injured in crashes than those using seat belts alone. Since seat belts along with vehicle seats are designed for adults, the institute said, it's important for boosters to fit children correctly to provide the proper restraint.

Take a look at the institute's booster rankings:

BEST BETS

Britax Frontier 85 (combination highback)

Chicco Keyfit Strada (dual highback)

Clek Oobr (dual highback)

Cosco Juvenile Pronto (dual highback)

Cybex Solution X-Fix (highback)

Eddie Bauer Auto Booster (dual highback)

Evenflo Big Kid Amp (backless)

Evenflo Maestro (combination highback)

Graco TurboBooster Crawford (dual highback)

Harmony Baby Armor (dual highback)

Harmony Dreamtime (dual backless)

Harmony Dreamtime (dual highback)

Harmony Secure Comfort Deluxe (backless)

Harmony Youth Booster Seat (backless)

Maxi-Cosi Rodi XR (dual highback)

Recaro ProBOOSTER (highback)

Recaro ProSPORT (combination highback)

Recaro Vivo (highback)

Recaro Young Sport (combination highback)

Safety 1st Boost Air Protect (dual highback)

The First Years Pathway B570 (highback)

GOOD BETS

Britax Parkway SG (dual highback)

Combi Kobuk Air Thru (dual backless)

Combi Kobuk Air Thru (dual highback)

Evenflo Symphony 65 (3-in-1 highback)

Graco TurboBooster Sachi (dual highback)

Graco TurboBooster Wander (dual highback)

Maxi-Cosi Rodi (dual highback)

BOOSTERS THAT MIGHT WORK FOR SOME KIDS IN SOME CARS

Britax Parkway SG (dual backless)

Chicco Keyfit Strada (dual backless)

Clek Olli (backless)

Clek Oobr (dual backless)

Clek Ozzi (backless)

Cosco Ambassador (backless)

Cosco Highback Booster (combination highback)

Cosco Juvenile Pronto (dual backless)

Eddie Bauer Auto Booster (dual backless)

Evenflo Big Kid LX (dual backless)

Evenflo Big Kid LX (dual highback)

Evenflo Big Kid No Back Booster (backless)

Graco Nautilus Elite Monti (combination backless)

Graco Nautilus Elite Monti (combination highback)

Graco Nautilus Matrix (dual backless)

Graco Nautilus Matrix (dual highback)

Graco No Back TurboBooster Cameo (backless)

Graco TurboBooster Baker (backless)

Graco TurboBooster Crawford (dual backless)

Graco TurboBooster Sachi (dual backless)

Graco TurboBooster Wander (dual backless)

Maxi-Cosi Rodi (dual backless)

Maxi-Cosi Rodi XR (dual backless)

Safeguard Go Hybrid (combination backless)

Safety 1st Boost Air Protect (dual backless)

Safety 1st Summit (highback)

Safety 1st Vantage (highback)

Safety 1st Ventura (highback)

Sunshine Kids Monterey (dual backless)

Sunshine Kids Monterey (dual highback)

The First Years Compass B505 (highback)

The First Years Compass B510 (highback)

The First Years Compass B530 (highback)

The First Years Compass B540 (highback)

Volvo Booster (dual backless)

Volvo Booster (dual highback)

NOT RECOMMENDED

Eddie Bauer Deluxe (combination highback)

Eddie Bauer Deluxe 3-in-1 (highback)

Evenflo Express (combination highback)

Evenflo Generations 65 (combination highback)

Evenflo Sightseer (highback)

Harmony Baby Armor (dual backless)

Safety 1st All-in-One (3-in-1 highback)

Safety 1st Alpha Omega Elite (3-in-1 highback)