However, larger countries may have more general information overall given the more detailed monitoring of groundwater hotspots (e.g. United States). Lastly, precipitation-abundant countries for which groundwater is not as important a resource, and which have predominantly rain fed agriculture, do not dedicate many resources to groundwater quantity measurement, resulting in a general lack of information (e.g. see Council of Canadian Academies, 2013:93). Overall, groundwater represents a major portion of usable water resources, accounting for 96% of liquid freshwater (UNESCO, 2008). Groundwater reserves are estimated to be over 20 million km3, of which 40% is freshwater.