The most common way energy is transmitted through a city is by overhead energy transmission network lines. A major benefit of overhead power lines is that the costs are much lower than underground transmission. Some of the disadvantages are that overhead transmission lines are likely to be affected by adverse weather conditions, which can lead to power outages. This FACT indicates the percentage of overhead energy transmissions networks in each state. The state with the highest percentage of overhead energy networks is Tasmania, at 90.5 percent. The state with the lowest is the Western Australia, at 75.7 percent. The data are from the years 2014 to 2015.