Back\lay £ volumes

Can anyone tell me when did the volumes drop to current levels and why?1
1.26    €1,835         
1.21    €2         
1.24    €2         
1.25    €24,926
For odds around 1.25 for example I remember being as least 2-3 times more volume being available on average.

Bot owners dropped out and only Betfair remains as a market maker?

Thanks.