Astronuc

At 212°F, 14.7 psia, liquid water has a specific volume of 0.016716 ft³/lbm and steam has a specfic volume of 26.80 ³/lbm, which is a volume ratio of ~1603 : 1 of steam:water.

Ref: http://www.eas.asu.edu/~holbert/eee463/SteamTable.pdf