There's the standard Lansweeper created Chart: Eventlog errors last 14 days in the report section.
Code below:
Select Top 1000000 Convert(nVARCHAR(10),tblNtlog.TimeGenerated,102) As Thedate,
Count(tblAssets.AssetID) As Total
From tblAssets
Inner Join tblAssetCustom On tblAssets.AssetID = tblAssetCustom.AssetID
Inner Join tblNtlog On tblAssets.AssetID = tblNtlog.AssetID
Where tblAssetCustom.State = 1 And tblAssets.Assettype = -1 And
tblNtlog.Eventtype = 1 And tblNtlog.TimeGenerated > GetDate() - 14
Group By Convert(nVARCHAR(10),tblNtlog.TimeGenerated,102)
Order By Thedate Desc