Need help with writing an assertion for count in response

I have a tag called <n1:lineOfBusiness></n1:lineOfBusiness> in my XML response for which i see different values in different nodes. The various values for this tag are VIDEO, VOIP, HIGH_SPEED_DATA etc..

I want to write an assertion which will give me the count of VIDEO lineOfBusiness, count of VOIP lineOfBusiness etc..

Please let me know which is the best assertion I can use and the logic in writing the assertion.

Note : Im new to groovy scripting.