Hubscore mainly depends on your account's age, number of hubs written, traffic, and general level of activity on the site (commenting, q&A, forum posting). But your hubscore has no bearing on your earnings, and it's not necessarily a reflection of the quality of your writing.
If you wrote very good articles on obscure topics that few people searched for, and you didn't comment a lot on other hubs/questions/forums, you would probably have a low hubscore compared to people with the same number of hubs. The number doesn't mean anything though. Like the accolades, it's mostly to encourage participation on the site.
As of this moment, your current score of 78 is about average for an account with 9 hubs.