While both Google and Apple are enjoying their growth in the U.S. smartphone market, Research In Motion experienced a decline in the first quarter of 2011, according to a new report from comScore.

Apple surpassed RIM for the second spot in the smartphone platform market during the period between January and April. According to the report, Apple accounted for 26 percent of the market in April, while RIM occupied the third slot with 25.7 percent.

Overall, more than 74 million Americans owned smartphones during the studied period. This represents a 13 percent increase from the fourth quarter of 2010, comScore stated.

Google and its popular Android mobile operating system held onto the No. 1 position, increasing its market share from 31.2 percent to 36.4 percent between January and April. Meanwhile, Microsoft and Palm rounded out the top five with 6.7 percent and 2.6 percent of the market, respectively.

As Americans continue to purchase Android-based smartphones and mobile phone accessories to support their handsets, experts predict Google's market share will continue to grow. According to figures from IDC, Android will represent 45.4 percent of the global smartphone operating system market by 2015.