These figures are pretty consistent with what I've seen
over the years. I've worked with financial institutions since the inception of
the Verified By Visa (VBV)/MasterCard SecureCode (MCSC) services and have seen
a very low participation rate from both financial institutions and merchants.
However, I'd guess that if you looked at the number of transactions that were
actually completed using these services instead of the number of retailers that
have it available on their websites, the percentages would be far lower.

Just because an Internet retailer participates in VBV or MCSC doesn't mean
the transaction will be completed using one of them. The individual cardholder
still has to have set up his or her card previously in order to
complete the transaction using one of the services. One of the setup
parameters for both of the services at the financial institution level allows
cardholders to opt out of the registration process indefinitely. Cardholder
participation rates at many of the financial institutions I've worked with
have been very low (less than 10%) since the services were introduced years
ago. Since VBV and MCSC were never made mandatory for financial
institutions, some institutions have chosen not to participate at all. So
even if the retailer is using the Visa and MasterCard authentication
services, the chance that the cardholder will use one of them to
complete the transaction is still pretty low.

While VBV and MCSC offer better protection
against online fraud, there is little incentive for individual cardholders to
set up the services. As Hitoshi Anatomi pointed out in his comment, for
cardholders it's just another password to manage. However, Visa
Checkout was just introduced recently. It is an authentication system
with the added ability to provide consumers a much simpler checkout
process. So perhaps this is the incentive cardholders need to begin
using authentication systems. My guess is that at some point
within the next few years online authentication will be required of all
transactions due to increased fraud and cardholders will have to participate,
like it or not.