Google has a great tool on their “think with Google” website. By analyzing data from Google Analytics, they are able show how each of the marketing channels affects online purchase decisions for different industries and countries.
For example, if I were to compare how marketing channels for medium sized businesses in the beauty & fitness industry influence the purchase decisions in the U.S. vs those in Japan, I get some interesting differences. In Japan a Display Click is more of an assist interaction while an Organic Search a last interaction, when comparing medium sized businesses in this industry in the U.S. And for both countries Social is more often an assist interaction while Direct a last interaction.
Link to the Google tool is HERE