It is narrated from Sayyiduna al-Mustawrid bin Shaddad (may Allah be pleased with him); he said: I heard the Messenger of Allah (peace and blessings be upon him) say: "Indeed, every nation has an appointed term, and the term of my Ummah is one hundred years. So when one hundred years have passed over my Ummah, there will come to it what Allah has promised it."
Ibn Lahi'ah said: What is meant by this is the abundance of trials (fitan).
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17861