Here is a brief list of your travelling options:

Security status of -2.0 or higher = .9 systems
Security status of -2.5 or higher = .8 systems
Security status of -3.0 or higher = .7 systems
Security status of -3.5 or higher = .6 systems
Security status of -4.0 or higher = .5 systems
Security status of -4.5 or higher = Death in Empire space