Hey, CM!

Oh! The progress bar checks your survey for questions, descriptive text, and pages to render the progress. Since you have only two pages, 2 questions on the first page and a thank you message on the final page, it sees you're on page 1, and haven't gotten to the final page, so renders at 50%.

For such a short survey, I would recommend simply removing the progress bar. You can do this by clicking on “Look & Feel” just under your “Edit Survey” tab, then checking the box for “Remove Progress Bar”.