check_nt & perfmon returning incorrect units



I’m trying to put together a few check_nt performance monitor checks. I have the checks returning good data, but the units are not correct.

Here is one example

define service{
        use                     generic-service
        host_name               xxxx
        service_description     SQL Server: Page Life Expectancy
        servicegroups           sql_server_perfmon
        check_command           check_nt!COUNTER! -l "\\SQLServer:Buffer Manager\\page life expectancy","Page life expectancy: %.f" -w 1000 -c 350
        process_perf_data       1
        action_url /nagios/pnp/index.php?host=$HOSTNAME$&srv=$SERVICEDESC$

This appears to return correct data, but the units are in percent. I have tried various syntax combinations (%%.f, %.f%, etc) without success.
Also, in the performance graphs the Label and Units appear as Page_life_expectancy __%.f. How can I fix this??

Thank you