I suppose if you average it out over the life of the boat to include sails, rigging and the inevitable upgrades to elctronics etc combined with annual running costs of shore storage, insurance and the like its probably not far off. A lot will depend on how much work you can and are prepared to do.

Amoret has its own account which SWMBO keeps track of, I prefere not to look but with in excess of Ł30K spent on refitting over the last 2 years with me doing much of the work its more than 10%