By Alexei Oreskovic SAN FRANCISCO (Reuters) – Google Incs Internet business revenue grew 19 percent in the first quarter, falling short of Wall Street targets as the price of its online ads continued to decline. Shares of Google were down 5.7 percent at $525 in after-hours trading on Wednesday. The number of paid clicks by consumers on Googles ads increased by 26 percent year-on-year in the first quarter, while the average cost per click declined 9 percent. Googles core Internet business revenue was $15.42 billion in the first quarter, versus $12.95 billion in the year-ago period.