Print out a random string between certain characters from a text file

Hi I have a text file named "fortunes" with a lot of data containing many differens quotes. Each quote is separated with the character "%". What I am struggling to do is to make a code that will print out a random quote out the whole text file, meaning that the random print should contain a string that is between the separator(%). Does anyone have any suggestions of an easy fix to this? As you can see I have started on something, but I am not sure where to include to random. function in all of this. Thank you so much in advance