2019:
2018:
https://www.latimes.com/local/lanow/la-me-ln-flu-demand-20180116-htmlstory.html
2017:
https://www.theguardian.com/society/2017/sep/24/winter-flu-crisis-hospitals-overstretched
2016:
2015:
https://abcnews.go.com/Health/flu-closes-schools-flusters-hospitals-nationwide/story?id=28245734
2014:
2013:
2011:
2009: