It’s that time again: April comScore qSearch data are coming out tomorrow. But the financial analysts are releasing it first to their clients and others who’ve subscribed to their missives.

According to our source, comScore will report that both Google and Bing have made small, incremental gains since last month and seen modest growth since last year. One or both are growing, it appears, at Yahoo’s expense. AOL and Ask are basically flat.

Yahoo is at its lowest point to date and has recorded its eighth straight monthly decline in terms of market share. Our source believes that Yahoo’s share could sink quite a bit lower over time.

Here’s the comScore share breakdown for the past two months compared with a year ago:

Data source: comScore (5/12)

These data do not include mobile search query volumes. We know that many publishers are seeing a range of between 15 percent and 25 percent of their queries now coming from mobile devices. In some categories the percentages are much higher: restaurants for example where 40 percent or even 50 percent of traffic is now from mobile.

Google is far and away the dominant provider of browser-based mobile search query volume in the US.

Postscript: Now the official comScore numbers are out and they’re consistent with what we posted above.