Mine took 3 years because my ex wouldn't sign the papers,kept moving house and not telling me where to,then tried getting custody of our daughter just to spite me. As redcrx said,it all depends on if the couple agree on all aspects of the settlement etc.
Mine took about 4 months from beginning to end (but it was agreed and we sorted out the finances). We lodged the papers in Feb, decree nisi in March, decree absolut in May.