After measuring record high mobile sales in April, May and June this year, U.S. and U.K. affiliate network Affiliate Window says mobile sales were down slightly month over month in July as a percentage of retailer clients’ total sales. Mobile devices accounted for 20.6% of sales across the hundreds of advertisers in its network last month, compared with 20.9% in June.

Affiliate Window works with more than 10,000 web site operators that publish links to advertisers’ e-commerce sites and earn a commission on any sales generated from the traffic they send. The network generated 13,000 sales through smartphones and tablets on average each day in July, with 300 sales per hour coming from iPads, it says. Additionally 1.6 clicks in its network came from iPhones every second last month.

Meanwhile, Android devices are starting to catch up in m-commerce. The value of Android sales stemming from Affiliate Window’s ads tripled year over year in July and increased 6.15% compared to June, a faster growth rate than the iPhone’s 4.32% month-over-month sales increase, the network says.

Mobile sales from Affiliate Network ads are slightly down as a result of less mobile traffic, Affiliate Window says. Traffic from smartphones and tablets across its network in July made up 17.6% of total traffic, down from a peak 22.31% in May, it says. That percentage reflects an uptick in desktop traffic in July, the network says.

For July, Affiliate Window also reports:

• Clicks from Android and iPhone smartphones had similar conversion rates, 2.15% and 2.21%, respectively;
• Tablets generated the highest mobile conversion rate, 5%, and desktops converted at 2.61%;
• The iPhone has generated 22% of mobile sales so far in 2013; the iPad, 59%; Android smartphones, 15%; Blackberry smartphones, 2%; and other mobile devices, 2%.
• The average mobile conversion rate for tables and smartphones in July was was 3.17%, a tad below May’s peak rate of 3.84%.