It appears you are reading that graph incorrectly perhaps.
Very few RA-Aus aircraft have Lycoming and Continental engines and likewise fewer GA aircraft have Rotax engines so the numbers do appear to stack up correctly in that graph. The heights of the bars appear to be largely meaningless.
16 Jab failures in GA.
114 Jab failures in RA-Aus.
The ratios seem about correct.
To Jabba's point, as for whether the total numbers are too high and should or shouldn't include certain events for example, remains to be seen.
Taking these statistics to use for comparative purposes between manufacturers seems to be the go versus trying to analyze the validity of the total numbers, under the assumption that all injustices are applied equally.