Few dates have been given. It did exist during what, for Earth, was the 26th century AD ("Planet of the Daleks"). Although the events in Shoreditch that (seemingly) led to the destruction of Skaro took place in 1963 AD, the Hand of Omega was explicitly stated to have travelled in time on its way to Skaro's sun, so we don't know what its date of arrival was ("Remembrance of the Daleks").
We know that both the Time Lords & the Daleks used time travel to influence or alter the events of Skaro's history. The culmination of this was the Last Great Time War, about which we've little information, so we can't know what changes it caused or when those changes took place. That makes it impossible to work out reliable dates.