Clearing hard drive space and now have "backup" gb usage

I am in the process of cleaning the hard drive, getting rid of unwanted or duplicated files. Initially I noticed I had over 130gb in the "Other" section of the drive and after deleting several files now I have 75gb on "Other" but the "Backups" section went from 1gb to 65gb! What does that mean? I thought I had done a successful clean up only to notice that the available space continues to be the same. Any help or clarification would be appreciated.