[Harmless Teddy Bear]

Mr Lawson also revealed 20 per cent of the dietary intake was fish – which was considered a food for the poor as it was cheaper than red meat...

Eating fish on Friday and other holy days would make for a 20% fish diet.

[Tax-chick]

Fridays are 1/7 of the year. 40 days of Lent. 40 days of Advent. Vigils of the major feasts such as Annunciation, Ascension, and All Saints.

A little math on the back of an envelope gives me over 1/3 of the year as meatless days.