Vitamin D levels increased - even back in 2010
2X increase in % with > 40 ng/ml in eight years
Update: Vitamin D levels in US: percent having more than 40 ng doubled (2001-2010) - Dec 2016
See also VitaminDWiki
Pure North (Calgary) improves health by raising vitamin D to 60 ng
Best Vitamin D- 40 to 52 ng, achieved with 4000 – 6000 IU daily – Heaney Oct 2014
Vitamin D (40-70 ng) in Children’s Health – review Sept 2014
4 times fewer with vitamin D deficiency in just 4 years ( Connecticut) – March 2016

Announcement by GrassrootsHealth.net May 2016
Pink boxes added by VitaminDWiki