Conversion Rates

The following are my current conversion rate statistics over the past Four months:

21 consults booked
15 showed up for calls (6 no shows)
5 clients sold

Is the conversion rate calculated as the total including no-shows 5/21 (24%) or just the rate that I sold when actually having full sales calls 5/15 (33%) ?

I started off with a very high conversion rate (first three calls 100%) which then dropped off to a high number of ghosts i.e. “I want to sign up but I need to think about it” and then never hearing back. I am trying to figure out if there is a problem with a) my offer or b) my target audience or c) there is no problem and my statistics are good and I just need to keep going and get more consults.

Although both conversion rates aren’t drastically low, it feels to me that something is ‘off’ with how I have had 5 no’s on the run. I am holding back from investing marketing spend (social media promotion) until I figure this out.

Any insights?