Help – Why Are My Google Adsense Impressions Lower Than My Site Impressions?

As regular visitors may have noticed, Google Adsense adverts have reappeared on my blog. However, according to the Google Adsense reports the ads are only showing on around 1/10 of my pages.  If this is true obviously I want to fix it as I could be making ten times as much money. I’ve fired off emails to Google and Blogware to see if they can help. Any ideas why? All help appreciated.