Budgeting for a global PR programme

When planning a global PR programme, which of the following models do you typically use?

  1. Percentage of the advertising or marketing budget 15%
  2. Fixed as percentage of sales or turnover 7%
  3. Rigorously planned to deliver precisely the right resources in the right place at the right time 36%
  4. Budget is based on what we spent last year, give or take a bit 42%

Personally, I don’t believe those who answered three. It might be what you are meant to do, but in my experience it is nearly always 4.