Well, in my experience bear attacks are much more common than lion attacks. But lion attacks are usually fatal, while MOST bear attacks are not fatal.
Lions and black bears hunt humans for food. Brown bears generally only attack if they are sick, or to protect cubs, or over territory. They can all attack if you corner or frighten them.
This is why its commonly taught to play dead with a brown bear, but fight like a Honey Badger if attacked by a black bear or lion. Brown bears just want you neutralized, black bears and lions want to eat you.
This surprises most people. Most believe Brown bears are the eaters, but they very seldom hunt humans. If they happen to kill you while defending cubs, they just might eat you. But black bears have been known to follow people, then pull them from their tents and eat them, that's hunting.
Brown bears include grizzly bears. Brown bears live near the salt water coasts, while Grizzlies are brown bears that live inland. Thats why Idaho and Montana have Grizzlies, while Alaska has brown bears. They are the same species, but the coastal browns are generally bigger due to high salmon intake.
In my experience, Grizzlies are much more ornery and more likely to be nosey. A nosey bear is a dangerous bear. They approach you because they are nosey. Then maul you because you're too close.

What was the question?
Oh, lion attacks are more rare than bear attacks, but lion attacks are more often fatal.
Bear attacks are on the rise world wide. In Japan they recently called in the military to help with the bears. Bear attacks in Japan are out of control. The bears territory is being eaten away, and the people can't hunt them. Most people have no idea Japan has bears, but they have lots of brown bears and Asian black bears.