What is my Blended Tax Rate?

Hi I don't really know what I'm doing here. I was filling my taxes and I saw I had a 10% Blended Tax rate, and I'm just confused what it is, and why it's so high? I work part time and earned a little over 17,000 in wages last year. I do not own any stocks or investments or anything. I'm just confused why I didn't pay anything last year but this I have this really big tax this year.