@RishiSinha  I didn't see any House Keeping activities goes against that particular table. Hence  the retention period is as long as Customer wish to keep it. I've seen 2011 Hourly usage data even now. 

These are couple quaries I use often on MS SQL Server. You can either use thiese sqls or use AES/PDC to run the Enterprise Charts to get this information. 

Dailu Usage:

  SELECT pzUsageDay,COUNT(*) As 'NoOfOnlineUsers' FROM [DatabaseName].[dbo].[pr_daily_usage] 
  Where pzUsageDay >= '2018-08-01' and pzUsageDay <= '2018-08-31'and pzUserType = 'H'
  GROUP BY pzUsageDay,pzUserType
  Order by pzUsageDay DESC

Hourly Usgae by Node:

SELECT TOP 5000 [pzPeriodEnding] As 'Hr of the Day',pzNodeName,COUNT(*) As 'No Of Online Users Per Hr'
FROM [DatabaseName].[dbo].[pr_hourly_usage]
Where  pzPeriodEnding >= '2018-05-21' and pzUserType = 'H'
Group By pzPeriodEnding,pzUserType,pzNodeName
Order by pzPeriodEnding DESC

@RishiSinha

There is a OOTB activity Log-.TrimLog which accepts a concrete class and an ancestor of Log- class as a parameter

If you wish to purge data from Log-License-Usage-Hourly, you might want to try this activity.