Figure 6: Proportional measure of frequency for the search term “pain” by online users at the main google search page (www.google.com) over the time period 2004 – 2010 (x-axis). Each measured time point is expressed as a normalized percentage of the maximum search frequency. Results are screen shots from the authors’ computer using Google Insights for Search (http://www.google.com/insights/search/#; accessed: April 30, 2011).