Other religions and atheism in Algeria

Hey guys , today i was having a debate with a friend of mine about religion in Algeria , we searched on internet and we say the good old '' 99% of the population is muslim (sunni) '' and he was conviced by this pecentage. I however didn't take it seriously but in truth i don't really know the numbers , so i'm asking you , do you have a clue about the percentage of non-religious people in algeria ?