extend_ax.Rd
Extend ax values for ages 75-105 using HMD regression parameters
extend_ax(empir_lt, hmd_ax_results)
data.table with columns: ihme_loc_id, sex, year, age_start, age_end, mx, ax
data.table with variables par_mx, par_smx, par_con, sex, age_start, age_end
returns empir_lt with the same variables, but modified values for ax for ages 75 and above