Hi, i'm wanting to create a more effective presentation/consultation for web development business. I'm looking for a source of free internet buusiness related statistics. ie. percentage of business with website, statistics for the effectiveness of a website for certain business. Where websites stand as far as outlay against income and clients generated etc etc ie. is it the most cost effective form of advertising available etc

Basically just some relevent statistics to quote when trying to pursaude a client into their own web presence.

Much appreciate any help as what i'm finding on google is mainly a paid service and i'm just looking for the basics at this stage.

Thanks