When converting from base count to coverage in [this document][1] they divide by 2.85 billion nucleotides:

```
POP BASE COUNT    COVERAGE      
ACB 3182037349066 1116.50433300561
```

Does build 37 of the human reference genome still only contain 2.85Gbp? It's the same figure as in [build 35][2]. In my reference sequence I count 3.1Gbp across the autosomes and the sex chromosomes. Have I missed something obvious here?

 [1]: ftp://ftp.1000genomes.ebi.ac.uk/vol1/ftp/sequence_indices/20130502.sequence.index.low_coverage.stats
 [2]: http://www.nature.com/nature/journal/v431/n7011/full/nature03001.html
I have computed this recently on GRCh37 :

<img alt="Human wholegenome mappability" src="http://i.imgur.com/D8QTz7j.png" style="height:325px; width:400px" />

(Mappability was computed with GEM program for reads of length 100 and 5 mismatches authorised)

EDIT : And so dividing by 2.85Gb gives you a more realistic estimate of your mean coverage since N's will never be covered by definition.