A Leaflet.js map created with Folium and the default D3 threshold scale. See the Gist for the python code to generate the dataframe. The map was generated with the following Python code:
map = folium.Map(location=[48, -102], zoom_start=3)
map.geo_json(geo_path=state_geo, data=state_data,
columns=['State', 'Unemployment'],
key_on='feature.id',
fill_color='YlGn', fill_opacity=0.7, line_opacity=0.2,
legend_name='Unemployment Rate (%)')
map.create_map(path='us_states.html')