Most likely from the very early 2000s if I recall correctly, but other members will probably be able to give you a more precise idea when it comes to dates. Numatic tend to make small, incremental changes over time instead of drastically redesigning their machines every so often. It's slightly different to the current model, but not majorly so.
Earlier versions had solid blue text on the front of the motor head, around the time this machine was made they switched to blue outline text as seen here. Still with the older style squared handle and rear power switch, however.
Later still the text was changed to white (so the same head could be used for all variants of the same model, regardless of tank colour specified). The carrying handle was also changed to the current rounded shape, allowing the machine and extension tubes to be carried together in the same hand. At the same time, the power switch was moved from the rear to the top of the motor unit.
Other changes: at some point the primary filter changed from the slick nylon Permatex type shown in your pic to the thicker fabric Tritex version; I *think* this coincided with the introduction of synthetic HepaFlo bags. The design of the small tools may differ slightly, and the combi floor head has been through a few different variations over the years. The latest version no longer has stainless steel tubes, but a grey epoxy-coated aluminium set which I'm not as keen on.