There is a set of standards that have been worked out for what is expected with writing and typing per age group. These are called the Written Production Standards for Handwriting and Keyboarding grades k-8. They are research based, and were Sponsored by Zaner-Bloser in partnership with the American Association of School Administrators.
These are being shared with permission from the creators, and all of the documentation can be found at the website for handwriting in the 21st century (hw21). Handwriting without tears also has Standards for the Production and Presentation of Writing. And finally here is a chart that provides handwriting and keyboarding rates.