Look at the spread from #1 to #2. At young ages, the difference is pretty high, suggesting that young kids falling from things is common. In the middle age ranges, #1 and #2 are pretty close, suggesting that falling isn’t that different (from a statistical frequency POV) from the #2 option.
But then look at the split at the older age groups. Falling is by and far the biggest cause. By a ton. Starting at 45, the split just keeps growing. And these numbers are higher in general than any other age group, so they skew the “all ages” numbers by a lot.
So, while it is a major cause for all age groups, the effect size is very age related.