Doesn't sound like a big deal to you? Well it should because I've seen average latent sales in the 55%-60% range and the % varies from site to site and from product to product; especially when the product has a long sales process or sign-up page. Several companies that I'm aware only started tracking latents recently and up until then had a large % of sales generated from unknown channels.
Think you know everything now. Well there's a lot more to it especially when it comes to interpreting the number and running campaigns using latent sales. However, that's for another week.