Mike is conducting an experiment in which he places several different types of soil in a funnel and then pours one liter of water through each. He is careful to pack equal volumes of the soil samples tightly in the funnel and to make sure that only water makes it out of the bottom. He then records the amount of time it takes for half of the water to pass through the soil and out the bottom of the funnel. He records his data in the table below. Soil Sample Time (seconds)
Soil W 181
Soil X 27
Soil Y 119
Soil Z 50

Which soil sample is the least permeable?