They do report a decrease in many contries. As for meeting attendance, the majority of those who miss still believe and contribute to their religion. The ones that stop altogether are called innactives and taken off the reports. So, yeah, the numbers are accurate and frankly, 8.5 millions is not something to brag about.
Imagine a sales rep braging about making one or two sales in over 30 years!! That's what the JWs are doing! After billions upon billions of hours in the field ministry, and just about the same in monney for producing all their teaching matterial, all they have to show for is an increase by 2.
Worst: When you ask anybody on the street what JWs preach about, the majority won't really know much about them. Yeah, they knock on people's door and they don't take blood and celebrate christmas. But the "good news"? No idea. There message is not getting through. Considering the gigantic amount of investment they placed into this, the results are very disapointing.