Depending on the type of bomb, a very high chance of it still being very dangerous. Many of the WW2 explosives are stable and dangerous for a long time, and numbers of them become more unstable with age.
The type of detonator also plays a part in whether it is more dangerous than when it was dropped. The time-fuse detonators are the very worst type for instability with age.
A sizeable percentage (up to 10%) of WW2 ordnance never detonated, some due to the way they landed, some due to assembly or manufacturing errors.
German cities that were heavily bombed during WW2 are not places I would choose to live today.
Smithsonian mag.com - Unexploded bombs left in Germany. 2000 tons of UXB's discovered annually.