Your account also has about 5,000 Steem delegated to it, so you're voting with about 8647 SP. The range I saw in my observations ran from about 10% through about 45%. For your effective SP, that would range from 16 SP to 75 SP per week (including curation rewards + blockchain inflation).

Looks like you got about 21 SP last week in curation rewards. Adding in blockchain inflation would put you around 16% APR, so that puts your account solidly in the same range.

To be in the same range without the delegation, the curation rewards for an account with 3650 SP would run from about 5-20 SP per week.

It's important to note that this was a snapshot of a small number of accounts at a single point in time. It's interesting to observe, but not really possible to draw any long-term conclusions from it, so I don't really suggest striving for any particular number.