Why don’t you do it by month of year.
EX. key(keyword_2012-07)=>value(“DailyList”:[{“01”:“firstdayofmonth”},{“02”:“second-day”},{},{“30”:“lastday”}]"),
This way the json document does not get to big b/c it only has 28-31 days and you has a max 12 documents per keyword per year.
To get all the data for the year you make a BulkGet([keyword_2012-07,keyword_2012-06])