This question refers back to the famous definition of what constitutes lobbying. If we consider that it's a communication activity, so contact between a lobbyist and a public office holder, 5,000 may seem an appropriate or logical number. But if we take into account all the preparation behind these activities, I think it's fair to say that the number of people hired by this industry is much higher than that. I think a broadened definition would allow us to take into account all those people whose work contributes to the single contact or the single communication.
