Step 1: Translate the condition.
“For a digit $d_i$ and its follower $d_{i+1}$, $(d_{i+1}-d_i)=1$.”
So we count all consecutive pairs $(d_i,d_{i+1})$ where $d_{i+1}=d_i+1$.
Step 2: Scan the series.
The qualifying pairs are:
$(6,7)$, $(7,8)$, $(8,9)$, $(8,9)$, $(7,8)$, $(8,9)$, $(7,8)$, $(8,9)$, $(8,9)$
⇒ total $=9$ pairs.
\[
\boxed{9\ \text{pairs} ⇒ \text{More than four}}
\]