What constitutes a "modest" vs. a "substantial" majority?

From an Interest!Alert Enews story: "...A more modest 56% to 28% majority believes that churches and religious organizations have too little power and influence. Also, a 51% to 30% plurality feels that racial minorities have too little influence. Conversely, a substantial (57% to 23%) majority believes that TV and radio talk shows have too much political clout. "

The full story:
Large Majorities Believe Big Companies PACs Media and Lobbyists Have too Much Power in Washington