Most of the soft and a growing fraction of the harder X-ray background has been resolved into emission from point sources , yet the resolved fraction above 7 { \thinspace keV } has only been poorly constrained .
We use \sim 700 { \thinspace ks } of XMM-Newton observations of the Lockman Hole and a photometric approach to estimate the total flux attributable to resolved sources in a number of different energy bands .
We find the resolved fraction of the X-ray background to be \sim 90 per cent below 2 { \thinspace keV } but it decreases rapidly at higher energies with the resolved fraction above \sim 7 { \thinspace keV } being only \sim 50 per cent .
The integrated X-ray spectrum from detected sources has a slope of \Gamma \sim 1.75 , much softer than the \Gamma = 1.4 of the total background spectrum .
The unresolved background component has the spectral signature of highly obscured AGN .