If I delete all my Jotform submissions will that clear up my storage space?

I deleted all of my Jotform submissions to clear up some space, but it still says that I am over my 100 MB amount.

Deleting the submisisons with upload submission on them will do clear your account storage space used.

I checked your account/username  curbd, and  I can see that you are indeed on Overlimit Status already due to exceed limit in storage used.

This is because your jotform http://www.jotform.us/form/52948045116153 do still have existing submissions with uploads on them. You have not deleted them yet.

Please take cautions when deleting submission data because they are not recoverable once deleted. 

Hope this help. Let us know if you need further assistance.