You aren't blind :) We just had trouble fitting a y-scale on the top chart that was both clean and readable and didn't get in the way of the time slider... Howe

You aren't blind :) We just had trouble fitting a y-scale on the top chart that was both clean and readable and didn't get in the way of the time slider... However this is just supposed to be an overview of the trend - the proportional bar chart further down the page is the same data, plotted in more depth and explained further.