(1): The Earl of Sandwich's answer to grease-free cards - slice of meat and cheese slapped between two pieces of heavily-buttered bread - is no longer enough to satisfy today's consumers in search of a quick but healthy snack.
(2): It estimates that sandwich sales now amount to a whopping #3.3 billion ($48.3 billion) a year in an industry that employs more than 300,000 people - or more than the whole of the British agriculture industry.
A dash (-) is longer than a hyphen (-). A lot of people confuse the two, usually using the hyphen in place of the dash.
A hyphen links up words (e.g. grease-free cards), while a dash links up clauses (i.e. parts) within a sentence, marking a pause or a sentence break.
Note that (1) contains two dashes while (2) has only one. The reason is that in (2), the end of the clause is also the end of the sentence. If the end of the clause is not the end of the sentence (see 1), then we should use a second dash. Just imagine it as a pair of brackets: when you open a bracket, you have to close it as well.