In announcing its global sales figures for July, BMW issued an update on i sales, both for the month of July and YTD.
Here are the worldwide sales figures for i vehicles. Note that BMW doesn't break out i3 and i8 sales individually when reporting global numbers:
"A total of 2,221 BMW i vehicles were delivered to customers in July, an increase of 79.4% year-on-year. In the first seven months of the year, 14,784 units were sold around the world."