All right but Atlas/Delta launched 11 times in 2013, for example. So per launch the cost would be lower.
Yes; the chart shows only USAF numbers. If we make a simplistic assumption of 8 DOD launches/year (with NRO's contributions) and that launch service unit costs are the same as shown in the USAF budget projections, average per launch cost is $349M (down from $372M at 5 launches/yr).
It's hard to say much more with any justification as non-DOD launches (and some DOD launches) do not contribute to ELC or fixed program management costs.* If we assume all costs are shared pro-rata across all launches (including non-DOD), then while the per-launch cost goes down, most everyone except the DOD will be priced out of the market.
E.g., making an assumption of 12 launches/year with all costs paid pro-rata by all launches, average is ~$300M/launch. Beyond that, this discussion gets wobbly and the data thin or non-existent. For example, NRO (no information to speak of)--a few Delta IV Heavies in the mix could significantly skew the costs. Should all launch customers pay a pro-rata share for DOD-specific needs (e.g., ELC)? If not, is that an unreasonable subsidy? etc.
If the question is: How much does a single-core launch cost, and what might a non-DOD customer expect to pay for one? The first-order answer is the "launch services" line, plus maybe a bit of the "support" line, then add mission-specific services. If the question is: Why do DOD launches cost so much? The first-order answer is the "launch capability" line (amortized over launch rate), plus "launch services", plus "mission assurance", plus any mission-specific costs.
No but the fixed-cost contributions per launch from the Air Force are likely bigger than the average.
See above. The degree to which the USAF numbers inflate per-launch prices depends primarily on the split between USAF/NRO; for ELC it is 75/25%; for mission assurance 60/40%; and the ratio of flights by USAF and NRO. The USAF numbers and split with NRO are given for both ELC and mission assurance, so the NRO contributions are easily derived. The rest depends on what assumptions you make as to the number/ratio of USAF and NRO flights.
* Of the 11 launches you mentioned for 2013, 3 were NASA and 1 Navy. NASA and Navy did not contribute to fixed costs (ELC, mission assurance, or program management).