Left panel: evolution of ³He/H with time in the solar neighborhood. Data for the PSC (green filled circle) and local interstellar medium (LISM, orange filled triangle) are from Geiss & Gloeckler (1998) and Gloeckler & Geiss (1996), respectively. 1-σ and 3-σ error bars are shown with thick and thin lines, respectively. Right panel: radial distribution of ³He/H at the present time. The dots are HII regions data from Bania et al. (2002) (error bars are shown only for S209; see text for discussion). The triangle at R_G = 8 kpc represents LISM data from Gloeckler & Geiss (1996). The predictions from Models A, B and C are shown in both panels by the red full, blue dashed and cyan dotted lines respectively.