An important part of family history is recording one's personal history. Probably the best way to do that is to keep a journal and make regular entries in it. After university and before I got married, I did a moderate job of writing journal entries. I averaged one entry every three days. By 2006, when my first two children were toddlers, I was down to a pathetic rate of less than 1%.
In the annual report, I want to have a graph showing me how I've done on my journal. Have I been writing regularly? Have I been writing substantially? Have written more or less than in previous years. I'm not sure if this graph would be useful on a timeline or if it's better as an independent chart. Regardless, for the annual report, I think I'll use the metric of "words written" instead of "journal entries" written. That'll help me answer the question about substantial entries.
Collecting the data will be easy since I write my journal entries on the computer (or Palm Pilot and sync them). I have a program that counts the number of entries and it should be easy enough to modify it to count words too.