52*5 = 260 workdays
Minus 8 Bank Holidays = 252
Plus one day (since the year is 52 weeks and one day long) = 253
Plus one day in a leap year = 253.25 on average
Generally at least 300 - five days a week plus a number of Saturdays or Sundays (or both) covering emergencies. However, this depends on the hours the clinic is open, whether or not the clinic covers...
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